Publicaciones

Diatomaceous Soils and Advances in Geotechnical Engineering—Part II

Daniel Zuluaga-Astudillo, Carlos Slebi-Acevedo, Juan Carlos Ruge, Javier Camacho-Tauta and Bernardo Caicedo-Hormaza.
Buildings 2024, 14, 48.

In the geotechnical area, advances in diatomaceous soil research are laconic and mainly oriented towards understanding the primary soil response (typical characterization methods) considering observation and experience (failures in construction processes or unexpected laboratory results) more than following a scientific method. Coincident results have been evidenced in the correspondence between the content of frustules, the effective friction angle and the water retention capacity. However, the variables and processes that control some mechanical behaviors have yet to be documented in the literature, such as the level of fracturing of the frustules and its relation with interlocked behavior, compressibility and shear strength. In addition to the bibliographic background, SEM microscopy records are presented. These facilitate the understanding of the described phenomena. The images highlight the level of deterioration, the environment, the morphology and the pores present in diatoms of different origins. The morphology (as a function of the species) of intact or fractured frustules (depending on the stress record) affects the mechanical responses and volumetric variations of the diatomaceous deposits. Furthermore, this review presents some emerging research lines in diatomaceous soils, such as the subjection of structures to geotechnical centrifuge conditions, some constitutive models and the criteria for developing water retention curves.
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Monitoreo y evaluación del comportamiento sedimentológico y geotécnico en la Cuenca Alto Suárez con enfoque en la adecuación hidráulica sobre el Complejo Lagunar Fúquene, Cucunubá y Palacio, para la formulación de alternativas de manejo de los sedimentos

Ruge Cárdenas, Juan Carlos Olarte Garzón, María Camila Ortegón García, Sebastián García Vásquez, Jorge Eliécer
Corporación Autónoma Regional de Cundinamarca CAR. 2023. ISBN: 978-958-5480-75-9

El presente estudio técnico aporta conocimiento actualizado y novedoso sobre el comportamiento de los sedimentos y el comportamiento geotécnico local en el Complejo Lagunar Fúquene, Cucunubá y Palacio, que brindan el conocimiento técnico para la formulación de las alternativas para el manejo de los sedimentos. Es de amplio conocimiento que históricamente en el país y en la jurisdicción CAR, se ha prestado mayor atención a las variables hidrológicas tales como la precipitación, el nivel del agua, la velocidad del agua, el caudal, la calidad del agua; empero ha resultado difícil técnicamente estudiar el comportamiento de los sedimentos. De todas las variables hidrológicas que se monitorean actualmente es la que menos estaciones de medición tiene y es la variable que hidráulica e hidrológicamente requiere mayores esfuerzos para modelar e interpretar su dinámica temporal y espacial. El estudio técnico permitió establecer la dinámica de los sedimentos en el Complejo Lagunar Fúquene, Cucunubá y Palacio, cuerpos hídricos de vital importancia en la cuenca del río Suárez, especialmente para los municipios Ubaté, Cucunubá, Lenguazaque, Fúquene, Susa, Simijaca, Chiquinquirá, entre otros. Los aportes significativos del estudio se obtuvieron para los ámbitos: 1) monitoreo de sedimentos, 2) geología, 3) geomorfología, 4) hidráulica e hidrología, 5) geotecnia, 6) pérdida de suelo, 7) producción de sedimentos, transporte y arrastre de sedimentos, 8) proceso de sedimentación. Contiene, además, diversas propuestas de obras para el perímetro de los cuerpos lagunares (dársena de sedimentación, reforestación, obras para la disposición del material de dragado, jarillones, entre otras). La CAR aporta una vez más un conocimiento científico actualizado y novedoso, con énfasis en el comportamiento de los sedimentos en el Complejo Lagunar Fúquene, Cucunubá y Palacio con el ánimo de mejorar las condiciones sociales, económicas y ambientales de la región.
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Laboratory Analysis of an Asphalt Mixture Overlay Reinforced with a Biaxial Geogrid

Eduardo J. Rueda, Juan Gabriel, Bastidas-Martínez, Juan Carlos Ruge, Yeison Alayón and Jeisson Olivos.
Coatings 2023, 13, 99.

Geosynthetic materials have been demonstrated to be an accurate element in civil engi neering, specifically in the field of pavement. Regarding the implementation of these materials in asphalt mixture layers, geosynthetics, such as geotextile and geogrid, have been used to delay the crack propagation and/or increase the fatigue life. However, the use of these material is based on the experience learned in the field or results obtained from testing on a reduced scale in the laboratory. This research work aims at valuating the influence that geogrids have as a reinforcement to asphalt mixture layer samples. Within this context, in this work, two types of large-scale samples (with and without reinforcement) are subjected to a monotonic load under two support conditions (simple support and granular base). The results were summarized with the load-line displacement diagram, where parameters such as the peak load, displacement, stiffness, and work of fracture were analyzed. The results reveal that the asphalt layer with geogrid experiences a double benefit since it withstands greater magnitudes of load and delays the appearance of rutting problems. To conclude, the geogrid as a reinforcement for asphalt mixture layers strongly impact their mechanical behavior, increasing the service life of the pavement structure.
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The Use of Zinc Oxide in Asphalts: Review

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge, Carlos Zafra-Mejía.
Sustainability 2023, 15, 11070.

Zinc oxide (ZnO) is a wide-gap semiconducting material which is chemically stable at high temperatures and has been shown to be compatible with asphalt binders. Additionally, semiconducting nanoparticles such as ZnO could help to improve urban air quality. This has encouraged the use of this material as a binder and asphalt mix modifier. A review on the use of ZnO as an asphalt binder modifier was conducted in this study. Based on the review which we carried out, the following were mainly synthesized and described: the content of ZnO as a modifier, the mixing processes of the binder and the ZnO, the manufacturing process of the modified mix, the type of asphalt binder and/or modified mix, the tests carried out, general conclusions, and environmental effects. ZnO micro-particles increase the aging resistance of the asphalt binder (mainly to ultraviolet radiation (UV)). ZnO tends to increase rutting resistance and adhesion with aggregates, improving resistance to moisture damage. It also tends to improve binder fatigue resistance. At low service temperatures, the performance of ZnO as a modifier is unclear, and further studies should be performed. Few studies have evaluated the effect of ZnO on the environment when it is used as an asphalt binder modifier. Future studies should evaluate the effect of this technology on the environment, perform economic analyses, evaluate the physical–chemical interaction of the modified binder with the aggregate, and measure the long-term properties of asphalt mixtures. ZnO is viewed as an environmentally friendly material and as a promising modifier of asphalt binders for pavement construction.
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Desafíos en la definición de factores de seguridad en el diseño de estructuras geotécnicas

Juan Carlos Ruge, Óscar Hernán Vargas Villamizar, July Estefany Carmona Álvarez.
Revista Colombiana de Tecnologías de Avanzada. 2023, 40(2), 73.

En este artículo, se analiza y discute la información de una encuesta realizada a un grupo de estudiantes de posgrado en ingeniería civil acerca de cómo el concepto de factor de seguridad es interpretado y empleado en el diseño de estructuras geotécnicas. Los resultados obtenidos aportan a la comprensión de las variables asociadas al cálculo de un factor de seguridad, visto como un ejercicio que trasciende el uso de fórmulas matemáticas e involucra al criterio ingenieril, siendo un aspecto clave al momento de su aplicación en contextos reales.
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Natural Asphalts in Pavements: Review

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge, Carlos Zafra-Mejía.
Sustainability 2023, 15, 2098.

Natural asphalts (NAs) can be an economical and environmental alternative in pavement construction. Most studies have investigated them as binder and asphalt mixture modifiers due to their high compatibility with conventional asphalts. In this article, some of the studies carried out on the use of NA in pavements are summarized and described in a chronological order. The main aspects described in the reviewed studies were the type of asphalt binder or modified mixture, the type and content of the modifier, the manufacturing processes of the asphalt or modified mixture, tests performed, and main results or conclusions. In general terms, NAs show better performance as binder and asphalt mixture modifiers in high-temperature climates. Additionally, they tend to improve water and ageing resistance. As main limitations, it is reported that NAs tend to negatively affect the workability and performance of asphalt mixtures in low-temperature climates. Finally, recommendations for future study topics are provided at the end of this paper.
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Mechanical Resistance of Hot-Mix Asphalt Using Phosphorite as Filler

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge, Fredy Reyes-Lizcano, Juan Gabriel Bastidas-Martínez, Carlos Zafra-Mejía.
Journal of Materials in Civil Engineering 35(9):1

Phosphorites (PF) have small particle sizes and interesting chemical compositions to be used as filler in asphalt mixtures. The present study assessed the performance that a hot-mix asphalt (HMA) displays when the natural filler (NF) is completely replaced by PF. X-ray diffractometry (XRD), X-ray fluorescence (XRF), and scanning electron microscope (SEM) tests were carried out on NF and PF particles. Asphalt mastic was manufactured using a weight ratio of filler (NF and PF) to asphalt binder of 1∶1.2. Penetration, softening point, viscosity, and linear amplitude sweep test were performed on the asphalt mastic. The following tests were carried out on mixes manufactured with NF (control) and PF (HMA-PF): Marshall, indirect tensile strength, Cantabro, resilient modulus, permanent deformation, and fatigue under stress-controlled mode. Additionally, moisture damage resistance was assessed through the tensile strength ratio (TSR) parameter. The HMA-PF mix displayed a better performance in all the evaluated properties, without increasing the optimum asphalt binder content. PF as fillers could be an interesting alternative in the manufacture of HMA mixtures subjected to high temperature climates.
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Evaluation of water retention curves in soils with diferent fines content

Victor Hernández, María Camila Olarte, Juan Carlos Ruge, Juan Gabriel Bastidas, Camilo Ernesto Herrera, Iván Fernando Otálvaro.
Arabian Journal of Geosciences (2022) 15:878

Abstract: This research proposed to analyze the dependence on the water retention properties in granular samples (Guamo sand) regarding diferent contents of fnes (kaolin). The extended evaporation method (EEM) and dew point method (DPM) allowed the construction of the water retention curves (WRCs). These methods can determine the matric suction of the samples at volumetric water contents in the partially saturated state. The results revealed that the Guamo sand only showed signifcant suction values in the pendular state of the system. As the kaolin content in the samples increased, the desaturation process revealing high suction values, even when samples have up to 30% volumetric water content. The evaluation of the experimental methods was generated from a WRC setting using traditional constitutive models. The prediction capacity of each model is defned with the coefcient of determination, where the behavior of the data indicates more signifcant predictive potential in high suction ranges.
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Unsaturated Hydraulic Conductivity in Composite Porous Media.

Jhan Piero Rojas, Juan Carlos Ruge and Gustavo Adolfo Carrillo.
Applied Sciences 12(18):9058.

Determining the constitutive properties that describe the incipient hydraulic behavior of the materials, including the matrix domains and the distribution of macro and micropores, is crucial to analyzing the preferential water flow in saturated soils, ks, and unsaturated, ku. This study focused on determining the hydraulic conductivity in porous media under total and partial saturation conditions. The infiltration characteristics of three reconstituted soils were evaluated using five suction ranges employing conventional permeameters, an automated dual system, and mini-disk infiltrometers. The experimental cycles were carried out in granular soils with mixtures of diatomaceous soils, iron oxide (Fe2O3), and calcium carbonate (CaCO3) in 5–40% proportions. The differences between the granular microstructures of each material and the different hydraulic interaction mechanisms (suctione levels) significantly affected the values of ks and ku and the coupling between the pore domains and the defined water regime. Additionally, a lower impact was observed in the data set exposed to higher percentages of Fe2O3 and CaCO3 in different suction ranges, mainly due to a tension effect (meniscus) generated by suction in the granular skeleton. Since both parameters are mutually correlated and have a similar impact between methods and soil cores, ks and ku must be optimized simultaneously in each mechanism analyzed. The main findings of this work result in the confirmation that the unsaturated permeability decreases as suction is imposed on the sample. As well as the addition of different materials with Particle Size Distribution finer than the base sample, it also reveals a reduction in hydraulic conductivity, both saturated and unsaturated.
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Physical Modeling in Geotechnical Centrifuge of Foundations Supported on Diatomaceous Soils

Daniel A. Zuluaga-Astudillo, Carlos J. Slebi-Acevedo, Juan Carlos Ruge, Marıa Camila Olarte.
Indian Geotechnical Journal. 2022. 53(3).

Diatomaceous soil deposits have been found in different parts of the world. However, until recently, its applications only existed in the field of agricultural engineering and agronomy. Within geotechnical engineering, there are still few studies on the subject. In this context, the advances found in the literature highlight that these materials are characterized by presenting geotechnical responses different from those dictated by traditional soil mechanics. One of the points of interest is related to the high values of resistance to shear that they can present, even when they are within clay matrices. Therefore, it is necessary to investigate the behavior of these deposits so that the physical and mechanical responses can be known in detail when subjected to stresses transmitted by a foundation structure. Thus, this study employs reduced scale models installed in a small diameter geotechnical centrifuge. The load and displacement trajectories of shallow and deep foundations in artificial soils built from a kaolin base with different dosages diatomaceus soils of different genesis are presented.
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Assessment of the asphalt mixtures properties subjected to a flexural strength

JC Ruge, HA Rondon-Quintana and JG Bastidas-Martínez.
Journal of Physics: Conference Series 2153 (2022) 012001

Abstract. Fatigue cracking by loading is one of the main mechanisms of damage to asphalt mixtures in service. Several studies worldwide have been conducted to try to understand the response that hot-mix asphalt undergo under this mechanism of damage. Despite the above, the fatigue phenomenon in asphalt mixtures is still not fully understood. The current research hypothesizes that the response under repeated loading of asphalt mixtures in fatigue tests can be more clearly understood through the one obtained under monotonic loading. For this reason, this study presents the results of the first phase of the research in which beams of asphalt mixtures were subjected to flexion using monotonic loads. The above, to correlate the evaluated properties with those obtained in a second phase where the response of the beams under repeated load (fatigue) will be measured. Beams made of two hot-mix asphalt mixes, two asphalt contents, and two different thicknesses were subjected to flexural strength tests. From the tests, the modulus of rupture, the maximum monotonic load that supports the beams in the failure state, the displacement in the failure state, and the relation between load and displacement were obtained. As a general conclusion of the study, it was obtained that the response experienced by the beams subjected to monotonic load has a broad correlation with the reported in the reference literature.
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Programa de ensayos tipo Round Robin para la caracterización física de la arena del Guamo

JC Ruge, F.A. Molina-Gómez, M.C. Olarte, J.F. Camacho-Tauta, O.J. Reyes-Ortiz, et al.
XVII Congreso Colombiano de Geotecnia 2022. Memorias.

Esta investigación presenta los resultados de un programa conjunto de pruebas tipo Round Robin Test (RRT), centrado en la caracterización física de la arena del Guamo. La arena del Guamo es un suelo transportado aluvial colombiano ampliamente utilizado con fines de investigación e ingeniería en el país. Las pruebas cooperativas fueron realizadas por once laboratorios académicos nacionales, los cuales evaluaron mediante siete réplicas diferentes parámetros físicos del material bajo estudio. La selección de los procedimientos de prueba no se indicó intencionalmente, con el objeto de comparar las diferencias entre los resultados experimentales. Tampoco se fijó un método de ensayo específico; por el contrario, se indicó que cada participante podía escoger libremente la metodología (estandarizada o no estandarizada) que considerara pertinente para medir cada una de las propiedades físicas mencionadas. Los datos proporcionados por todos los participantes se analizaron e interpretaron mediante técnicas estadísticas, exploración descriptiva, y análisis de métodos de varianza
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Analysis of the goodness of fit of the San model for the calculation of the removal percentage of flocculent particles with low initial turbidity values in the problem water

Diego Alejandro Pulgarín-Montoya, Juan Sebastián De Plaza-S, Juan Carlos Ruge-C. & Paulo José Rocha de Albuquerque.
Revista DYNA, 88(219), pp. 28-34. October - December, 2021.

En este estudio se determina el grado de bondad de ajuste que presenta el modelo de San para el cálculo del porcentaje de remoción de partículas floculentas, cuando la turbiedad inicial en el agua problema es baja. Para esto, se hace el análisis de frecuencia de los datos históricos de turbiedad que ingresan a cuatro plantas de tratamiento de agua potable ubicadas en el departamento de Cundinamarca (Colombia), las cuales arrojan valores que oscilan entre 0.60 y 15.08 UNT (Unidades Nefelométricas de Turbidez). La coagulación del agua se hizo utilizando sulfato de aluminio tipo A y la prueba de sedimentación se realizó en una torre de sedimentación con el fin de determinar la turbiedad remanente en el agua que permite calcular el porcentaje de remoción para diferentes tiempos de sedimentación y a distintas profundidades.
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Hydraulic modeling of combined sewers overflow integrating the results of the SWMM and CFX models

D.A. Pulgarín, J.S. De Plaza, J.C. Ruge, J.P. Rojas.
Rev. int. métodos numér. cálc. diseño ing. (2021). Vol. 37, (1), 14.

This study proposes a methodology for the calibration of combined sewer overflow (CSO), incorporating the results of the three-dimensional ANSYS CFX model in the SWMM one- dimensional model. The procedure consists of constructing calibration curves in ANSYS CFX that relate the input flow to the CSO with the overflow, to then incorporate them into the SWMM model. The results obtained show that the behavior of the flow over the crest of the overflow weir varies in space and time. Therefore, the flow of entry to the CSO and the flow of excesses maintain a non-linear relationship, contrary to the results obtained in the one- dimensional model. However, the uncertainty associated with the idealization of flow methodologies in one dimension is reduced under the SWMM model with kinematic wave conditions and simulating CSO from curves obtained in ANSYS CFX. The result obtained facilitates the calibration of combined sewer networks for permanent or non-permanent flow conditions, by means of the construction of curves in a three-dimensional model, especially when the information collected in situ is limited.
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Incorporação de pó de agregados reciclados de concreto como fíler em misturas asfálticas

Juan Gabriel Bastidas-Martínez, Juan Carlos Ruge Cardenas, Liosber Medina García, Robinson Andrés Giraldo Zuluaga.
Matéria (Rio J.) 26 (03) • 2021

A geração e o gerenciamento de resíduos sólidos industriais consideram-se uma problemática ambiental no mundo. Vários estudos têm se concentrado na utilização de resíduos da construção civil no âmbito da pavimentação. O objetivo deste artigo é avaliar o uso do pó de agregados reciclados de concreto RFPA (Recycled Fine Aggregates Powder) no Concreto Betuminoso Usinado a Quente (CBUQ). Para tal fim, se fabricaram três tipos de misturas asfálticas: a mistura de referência com materiais convencionais e dois misturas de estudo com substituição do 3% e 6% do filer natural pelo RFAP (composição total da massa da mistura). Avaliou-se a resistência sob carga monotônica das misturas (Ensaio Marshall e Tração Indireta-RT) e a resistência ao desgaste Cântabro. Uma análise de variância (ANOVA) foi realizada para verificar se os resultados obtidos eram estatisticamente significativos. Ao substituir a 3% do fíler da granulometria pelo pó RFAP, obteve-se um comportamento mecânico satisfatório sob a ação das cargas monotônicas, embora houvesse aumento da perda de massa no ensaio Cântabro. Os resultados evidenciam que a utilização do RFAP da forma proposta é viável desde o ponto de vista técnico e ambiental, por permitir uma forma de disposição final segura de resíduos.
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Effect of aging on the physical-mechanical characteristics of an asphalt mixture with rubber

J G Bastidas-Martínez, J C Ruge, R A G Zuluaga and L Medina.
Journal of Physics: Conference Series. IV International Seminar on Pedagogical Practice (2021).

This paper evaluated the physical-mechanical characteristics of two asphalt mixtures. One mix with conventional asphalt and the other with asphalt modified with recycled rubber grain. For this purpose, the asphalt mix designs were made by means of the Marshall methodology. Subsequently, asphalt mixtures were manufactured to analyze the action of monotonic loads (indirect tensile strength) and dynamic loads (resilient modulus). Previously, each type of asphalt mix was subjected to short- and long-term aging conditions, following Aastho guidelines. It is concluded that the incorporation of recycled rubber grain makes the changes in mechanical properties with aging not very noticeable in relation to mixtures without this material.
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Modelación Numérica de Excavaciones en los Suelos Blandos Bogotanos, Considerando el Efecto de Instalación de la Pantalla Pre-excavada

Camilo Herrera y Juan Carlos Ruge
Jornadas Geotécnicas y Estructurales 2021

Las excavaciones en zonas urbanas por lo general son verticales y en inmediaciones a infraestructura existente. La ingeniería de rutina considera solo el estado límite de esfuerzos (falla por cortante). Las afectaciones generalmente se asocian al estado límite de servicio (desplazamientos). El problema solo se puede resolver por métodos teórico-empíricos que permitan el análisis simultáneo de esfuerzos y deformaciones. Pero considerando la dependencia de la rigidez de los suelos en su historia de esfuerzos, los análisis suelo-muro, deben incorporar todas las solicitaciones generadas antes, durante y después de construida la pantalla. Esto debe incluir los efectos de construir la pantalla (excavación con lodo y vertido del concreto). En este trabajo presenta el análisis comparativo de dos modelos numéricos 2D de una excavación. Uno considera la instalación del muro pantalla y otro no dentro de los suelos heterogéneos de la formación Sabana. Los análisis permitieron encontrar que el no considerar los efectos de construcción de la pantalla genera una relajación de los empujes horizontales y una disminución del esfuerzo cortante movilizado. Esto ocasiona que los momentos flectores en la pantalla sean sensiblemente menores cuando no se considera los efectos de instalación.
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Permeability measurement in porous media under unsaturated paths

Luis Carlos Galvis-Velasco, Juan Carlos Ruge, Luis Carlos Galvis-Salamanca, Laura Pulgarín-Morales, Juan Gabriel Bastidas-Martínez & María Camila Olarte.
Revista DYNA, 88(219), pp. 123-130. October - December, 2021.

Understanding the flow through porous media when it is part of geotechnical-hydraulic structures has been a scenario calculated from the most unfavorable situation. The passage of water through the porous skeleton of the soil is considered in a saturated condition. Few studies to date consider partially saturated trajectories regarding the influence on the stability of a dam, reservoir, embankment, among others. Estimating the speed with which the fluid under analysis flows through a partially saturated media is challenging to perform by conventional methods. By contrast, nowadays, it is easy to obtain for saturated soil. This study aimed to measure hydraulic conductivity (coefficient of permeability) in granular soils using easily accessible laboratory techniques. The permeability in unsaturated conditions will be measured, varying the suction in the sample, which is an essential requirement when there is a situation of partial saturation. The results provided data on the permeability values that allow to obtain a very evident difference between both proposed conditions.
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Influence of the Diatomite Specie on the Peak and Residual Shear Strength of the Fine-Grained Soil

Carlos J. Slebi-Acevedo, Daniel A. Zuluaga-Astudillo, Juan C. Ruge and Daniel Castro-Fresno.
Appl. Sci. 2021, 11, 1352.

Diatomite is a powdering mineral mainly composed of diatom microfossils present in marine and lacustrine soils, which influences their physical and mechanical properties. Although many articles have been found in the literature concerning the influence of diatomite in the overall behavior of natural soils, few research efforts have been carried out to evaluate the influence of the diatom microfossil species on their shear resistance. Therefore, in this research, the influence of the diatomite species and the content in the peak and the residual shear strength of diatomite-fine grained soil mixtures was analyzed using the annular shear strength test. Scanning electron microscopy (SEM) and Atterberg limits were also carried out as additional tests to explain the interlocking effect between the microfossils and the soil. Overall, both diatomite species increased both peak and residual shear strength of the soil similar to dense sands. Nevertheless, the Mexican species reveal higher friction angle values compared with Colombian species.
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Influence of the inclusion of synthetic compounds on the plasticity of kaolinitic clays

María Camila Olarte, Juan Carlos Ruge & Paulo José Rocha de Albuquerque.
Arabian Journal of Geosciences (2021) 14:1581

Clay soil is typically an electrically charged porous tissue whose behaviour is dependent on possible variations in the composition and concentration of the interstitial water. Various complex mechanical impacts can be generated from the physicochemical reactions produced within the compact sets of elongated sheets, often called tactoids. If the chemistry of the used fluids varies appreciably, the natural response to cation exchange is affected, which results in intense physicochemical effects in the soil. In this article, five synthetic agents (Al2O3, Fe2O3, NaCl, CaCO3, and C2H5OH) were included in the kaolin, in different propor- tions, to explain the influence of the chemistry of these fluids on the chemical-mechanical behaviour of the clay soils. The artificial inclusion of these agents indicated specific changes in the material structure and the known paths of the fundamental Atterberg constants, ranging from the substantial reduction in plasticity according to the oxidizing agents to the considerable increase of this property monohydric solution.
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Influence of the interface modelling in numerical simulation of tied-back excavations

Juliet Alejandra Pellaton-Patiño & Juan Carlos Ruge.
Respuestas, 26 (1) January-March 2021, pp. 22-29,

In terms of numerical modeling, one of the aspects that mainly affects the earth pressure values of tie-back excavations is the friction or adhesion that is generated at the interface between the soil and the retention structure material (generally concrete). Typically, software providers based on the finite element method establish that the roughness value does not have a major influence on the results. However, when comparing the output data, in numerical simulations, this is not necessarily entirely true. Generally, this factor is simulated in the programs relating the interface strength with the soil strength. The current contribution aims to validate the influence of the variation of different parameters related to roughness or friction on the results of earth pressure in an anchored diaphragm wall. The results show high variations, with a high dependence on the mentioned parameters that are related to the modeling of the interface.
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Analysis of the dispersivity in soils by applying a modified test based on the pinhole method

L C Galvis, J C Ruge and M C Olarte.
Journal of Physics: Conference Series. IV International Seminar on Pedagogical Practice (2021)

The Pinhole test is an empirical probe with a qualitative classification foundation that identifies fine-grained soils with dispersive potential using hydraulic heads. However, the original technique was designed to identify dispersive clays. In some cases, it is misused as a quantitative test for measuring subsurface erosion rates. This paper presents a physicochemical modification to the exact test, based on adding a dispersant in the sample compaction water. For the quantitative evaluation of the susceptibility of the soil to generate internal tubification or piping, the effects of hydraulic load, flow, and orifice diameter before and after the execution of the test are explored—both for the samples treated with deflocculant and for those compacted using distilled water. Additionally, to complete the identification results, physical and chemical approaches were applied as methods of comparison. The results obtained from the altered soils indicate a significant increase in the clay fraction among the samples at the end of the test and gains of 3.7 and 6.2 times the initial diameter. The study demonstrates that the modified test is suitable for identifying non-dispersive soils before raising the percolation pressure. This modification is helpful for the improvement of the test because it helps to understand the procedure better and allows to calibrate the apparatus used.
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Experimental assessment of swelling potential in montmorillonite soils

J C Pérez, J C Ruge, J P Rojas, J A Orjuela, and J R Cáceres.
Journal of Physics: Conference Series. IV Workshop on Modeling and Simulation for Science and Engineering (2021)

The study of the physicochemical activity of clays is essential to understand the mechanical-hydraulic behavior. The experimental analysis of the expansivity of soils is linked to the content of clay minerals present in the tactoid tissue, which affect is directly in proportion to the volumetric change that soil may undergo. This work aims to carry out an analysis to understand the expansive behavior of the proposed clay materials, using different techniques, both conventional and modern. For this purpose, the bentonite clay used with a majority montmorillonite component was analyzed through petrographic tests and images analysis. The samples with a base material and different contents of montmorillonite were prepared. Montmorillonite is a clay mineral with a very high swelling potential because even when it was used in low proportions on a sandy base material, the influence of the material is strong and the expansivity remained high.
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Novel method for stress history analysis in normally consolidated clays

J H Martínez, J C Ruge, J P Rojas.
Journal of Physics: Conference Series. IV Workshop on Modeling and Simulation for Science and Engineering (2021)

The historical investigation of stresses in a clay material is essential to predict the compressible behaviour of a soil layer that, in most cases functions as a foundation support of superstructures. Because the stresses underwent in the geological past provide useful information to understand the response of the soil today. There are numerous methods for the interpretation of the preconsolidation stress, defined by the standard unidimensional consolidation test. The concept of preconsolidation stress is extremely useful in the geotechnical field to analyze and estimate settlements in a clay deposit, in addition to normalizing other parameters for comparative purposes. Through mineralogical analysis and consolidation tests based on different models for the estimation of the vertical consolidation coefficient, preconsolidation stress is evaluated by applying disparate constitutive methods. In order to observe the dispersion of results for a particular soil. A new technique is proposed for the determination of the preconsolidation stress prescribed in differential terms and with a high degree of objective interpretation.
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Comparación experimental entre la sensitividad y la cementación en el comportamiento no drenado de suelos arcillosos

Juan Carlos Ruge Cárdenas, Fausto Molina-Gómez, Renato Pinto da Cunha
Ingeniare. Revista chilena de ingeniería, vol. 29 No 1, 2021, pp. 109-119

En este artículo se presenta un estudio experimental que compara el efecto de la sensitividad contra el de la cementación, en la recuperación de las propiedades esfuerzo deformación en suelos arcillosos de la Sabana de Bogotá. La metodología de trabajo incluyó tres fases: (i) extracción de muestras; (ii) evaluación de las propiedades de los suelos en estado inalterado; y (iii) estabilización y análisis de resistencia de dichas muestras modificados materiales cementantes. Las muestras de suelo fueron tomadas en el municipio de Madrid (Cundinamarca, Colombia). Se desarrolló un plan experimental que incluyó ensayos de caracterización física y mecánica. En dicho plan se hizo énfasis en la evaluación de la resistencia al corte no drenada y los parámetros elásticos mediante ensayos de compresión inconfinada. Los suelos fueron compactados y estabilizados mediante la adición de dos productos químicos sólidos, carbonato de calcio y óxido de hierro. Los resultados entre las muestras naturales, remoldeadas y mejoradas fueron comparados mediante técnicas de análisis estadístico. De esta manera, se encontró que la implementación del óxido de hierro en este tipo de suelos permite obtener parámetros esfuerzo-deformación cercanos a los del estado inalterado después del proceso de remoldeo.
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Physical mechanical performance of asphaltic emulsions in road oil for flexible pavements

J G Bastidas-Martínez, J C Ruge, I J Paba, F Vasquez and J P Rojas Suárez.
Journal of Physics: Conference Series. XV Applied Mathematics Meeting and XII Statistics Meeting (2020)

The present study evaluated experimentally, the impact of the application rate, in terms physical and adherence, of four types of emulsions used as road oiling in two asphaltic layers for flexible pavements. Asphaltic layers are composed by an asphaltic base and a hot mix asphalt surface layer. To evaluate the adherence and physical properties, a shearing test was carried out. Four rapid set cationic emulsions were used, by means of three application rates of 0.33 l/m2 , 0.50 l/m2 , and 0.65 l/m2 (recommended values in Colombian road construction practices). The results demonstrate that an emulsion application rate of 0.50 l/m2 guarantees better adherence in the structural package. Also, that greater resistance against the sliding of the surfaces of the specimens in the shearing test, depends on the residual content of the asphaltic emulsion.
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Análisis numérico de excentricidad unidireccional en zapatas aisladas

Paula Andrea Rodríguez-Obando, Juan David Salazar-Niño, Juan Carlos Ruge-Cardenas.
Mundo Fesc, 10 (20), pp. 156-165 Julio-Diciembre, 2020.

La capacidad de carga última se define como la carga aplicada a un suelo mediante la distribución de una solicitación critica ejercida al material de soporte, valiéndose de un elemento geotécnico de conexión llamado cimentación. Según Terzaghi, la mayoría de las cimentaciones se diseñan bajo un concepto conocido como falla general por corte. Teóricamente, existe una influencia sobre el cálculo, detectada por el efecto de la excentricidad de la carga, transmitida por la columna de la estructura aporticada. Esta excentricidad puede ser causada por varios aspectos, en especial, superestructurales que son transferidos a la cimentación superficial. El estudio consta de un análisis numérico, usando un modelo computacional basado en el método de elementos finitos; y una evaluación mediante ecuaciones empíricas que son usadas en la cotidianidad de la ingeniería práctica. Los resultados muestran cierta similitud, donde se revelan valores conservadores en las modelaciones numéricas respecto a las teorías tradicionales.
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Asphalts and modified dense asphalt mixtures with rubber of military boots

Diego Andrés Lozano, Fausto Molina-Gómez, Juan Carlos Ruge, Luis Ángel Moreno-Anselmi & Juan Gabriel Bastidas-Martínez.
Revista DYNA, 87(212), pp. 120-128, January - March, 2020.

This article evaluates in the laboratory the physical and rheological properties of the modified asphalt cement (AC) with different contents of rubber (R) from used military boots. For the evaluation of the modified AC, laboratory tests of penetration, softening point, ductility, viscosity, short-term aging and determination of the rheological parameters in the DSR dynamic shearing rheometer were performed. Besides, the mechanical performance of a conventional asphaltic dense mixture (control) and three dense asphalt mixtures with modified asphalt cement with different rubber contents, wet-added, was evaluated by means of monotonic load tests (Marshall Stability) and dynamic (dynamic modulus). The physical and rheological evaluation of the AC modified with R indicates a significant increase in stiffness as a function of the R content. The asphalt mixtures studied, in reference to the control mixture, presented the same optimum content of asphalt and an increasing in the Marshall stiffness and dynamic modulus. Therefore, it was found that the addition of rubber from military boots used in the asphalt cement and later in the mixture, can be considered viable from the technical and environmental point of view, due to the improvement in the mechanical properties of these materials and to allow a form of correct final disposal of the rubber.
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Behavior of a draining mixture composed by recycled concrete aggregates and rubberized asphalt concrete

Juan Gabriel Bastidas-Martínez, Nicolás Infante Rodríguez-Joaquín, Hernán Darío Torres-Daza, Hugo Alexander Rondón-Quintana, Juan Carlos Ruge-Cárdenas.
Respuestas, 25 (1), January - April 2020, pp. 96-107.

Concrete waste is considered an environmental liability with a negative impact. However, this type of waste presents a high potential to be used as an alternative building material. Therefore, the present study aims to evaluate the applicability of substituting the conventional natural stone aggregate (CA) of a draining asphalt mixture (MD) by a recycled concrete aggregate (RCA). Firstly, RCA was physically characterized to be compared with the AC. Then, two MD mixtures were design with rubberized asphalt concrete (GCR by its spanish acronym): one using the conventional aggregate (control sample) and one with the RCA substituting entirely the CA. Experimental tests under monotonic load (indirect tensile strength - RTI) were conducted over the mixtures, as well as adhesion tests (susceptibility of RTI in wet and dry conditions and abrasion wear Cantabro). The results indicate that for MD mixtures with RCA, a higher content of asphalt is required than with CA. Additionally, it wasfound that the presence of higher asphalt content in MD-RCA mixtures increases its adhesion when compared with the control sample. Therefore, it can be concluded that the use the RCA for MD mixtures, in the proposed way, is technically and environmentally viable.
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Evaluation of Analytical and Numerical Techniques to Simulate Curtain Pile Walls in a Tropical Soil of the Federal District of Brazil

S. Jacazz, Y. M. P. de Matos, F. F. Monteiro, R. P. Cunha, J. C. Ruge & G. Gassler.
Geotechnical Engineering Journal of the SEAGS & AGSSEA Vol. 51 No. 2. June 2020

This paper is fruit of an active interaction between several universities/academics and the University of Brasília. It has focus on the design of retaining walls. This design is increasingly present in engineering projects for urban areas, given their continuous development. In the Federal District of Brazil, many retaining walls are built in order to optimize space. These excavations need retaining works in order to maintain the terrain in place and to avoid any collapse. The aim of this paper is to tentatively assess the behavior of retaining structures made of “pile curtain” by using existing commercial finite element (F.E.) and “winkler spring” type softwares. The case study is characterized by a 13m deep excavation founded in the well-known porous clay of Brasilia. The excavation ́sinstrumentation provided displacements along depth, used to evaluate the structure ́s behavior. In terms of the approach by using a winkler type software, the best technique to evaluate the subgrade reaction coefficient (modulus) was an empirical equation presented by Bowles (1988). For the numerical predictions with finite element method, the Hardening Soil model tended to show a slight better result when compared to the traditional Mohr Coulomb model. It is concluded that simple techniques, and experience of the engineer, are sometimes fundamental to better simulate such types of structure founded on complex unsaturated tropical soils.
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Assessment of an Asphalt Mixture employing a Blast Furnace Slag Pretreated with a Polymer

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge-Cárdenas and JuanGabriel Bastidas-Martinez.
International Journal of Advanced Science and Technology Vol. 29, No.4, (2020), pp.9105 – 9113

Blast furnace slags (BFS) could be used as substitutes of the coarse fraction of natural aggregates (NA) in the production of hot mix asphalts (HMA). However, its high porosity and absorption are generally seen as disadvantages in HMAs. For this reason, this study used a polymer employed in soil stabilization processes in order to partially fill the air voids of a BFS. Then, this pre-treated BFS material (BFS-SMK) substituted the coarse fraction of a NA in an HMA. The mechanical resistance and the moisture damage resistance was evaluated performing Indirect Tensile Strength and Marshall Tests. Additionally, Cantabro and resilient modulus tests were performed. An ANOVA - analysis of variance was carried out. As a general conclusion, the BFS-SMK could be used as a substitute material for NA in HMA.
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Assessment of Dissolved Air Flotation System for Wastewater Treatment in a Paper Industry

Carlos Alfonso Zafra-Mejía, Hugo Alexander Rondón-Quintana, Juan Carlos Ruge-Cárdenas.
International Journal of Advanced Science and Technology Vol. 29, No.4, (2020), pp.8672 –8679

The paper and cardboard industry has a high dependence on the proper use and wastewater treatment. Water is used in all production phases from the preparation and transformation of raw material to the dilution process in paper machine. The above industrial conditions require special attention to reduce the costs related with water and energy consumption in processes such as paper drying. The main objective of this paper is to evaluate the efficiency of dissolved air flotation (DAF) system in a wastewater plant of a paper industry. This industry manufactures cardboard, where corrugated and liner papers are produced. A comparative analysis is performed between two flocculants (Andifloc - FA and Nalco 68530 - FN) using the following water quality parameters: total suspended solids (TSS), electrical conductivity, and chemical oxygen demand (COD). On average, findings obtained for the FN flocculant displayed that TSS concentration in treated water decreased by 48.1% compared with the FA flocculant. Efficiency in the DAF system increased on average by 3.64%, and efficiencies of up to 97.6% were also observed for TSS removal. The findings also showed a decrease in COD concentration during the evaluation of FN flocculant. An average decrease of 16.2% in COD concentration during FN flocculant use was observed.
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Heat Treatment Effects on the Variation of the Specific Surface in Clay Minerals

J.C. Ruge, H.A. Rondon-Quintana, C.A. Zafra-Mejía.
International Journal of Advanced Science and Technology Vol. 29, No. 4, (2020), pp. 10741–10752

The clay minerals that compose the materials commonly known as clays, provide numerous characteristics that affect their mechanical behavior. One of the aspects that most affects the peculiar response of this type of materials is the specific surface area (SSA). This research aims to observe the behavior of SSA, when clay minerals with considerable ionic exchange are submitted to a heat treatment. The samples received different temperature stages and exposure times. The clay materials were characterized, in order to know their basic properties. Subsequently, two different methodologies were used to obtain the SSA, before and after the imposition of the temperature. In short, it was observed that the analyzed materials undergo extreme phase transformations, as the temperature was increased. The exposure time seems not to be an incident in the result obtained, at least for this research.
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Simulation of the Impact Generated on a River by the Wastewater Discharge From a Latin American City

Carlos Alfonso Zafra-Mejía, Hugo Alexander Rondón-Quintana, Juan CarlosRuge-Cárdenas.
International Journal of Advanced Science and Technology Vol. 29, No. 3, (2020), pp. 14875 – 14882

The continued growth of cities and industrial production implies an increase in pressure on surface water bodies, which are used as a water source or as receivers of wastewater discharges. Thus, mathematical models that relate wastewater inputs to the water quality in the receiving body are often used in the control and management of water resource. Globally, various studies and technologies have been presented for the simulation of wastewater discharges with the aim of improving water quality standards, especially to improve the life quality of the inhabitants by eliminating microorganisms harmful to human health. In this regard, water quality models have proved to be a useful tool in the strategic management of water resources. The main objective of this paper is to present an impact analysis generated by the wastewater discharge from a Latin American city on Magdalena River (Colombia). This analysis is carried out using the Qual2k model and considering the minimum and maximum flows of the river under study. The findings suggested that Magdalena River tended to self-clean in those initial 5 km due to the dilution of the wastewater discharge from the treatment plant. After these 5 km, biochemical oxygen demand (BOD5) and dissolved oxygen (DO) concentrations tended to decrease downstream toward the usual Magdalena River concentrations (15 km): 27.8 mg/l and 5.10 mg/l, respectively. This is in relation to the foretold minimum flows for Magdalena River and for a 0% pollutant removal scenario. The outcomes indicated in the 80% pollutant removal scenario that the receiving water source (Magdalena River) performed better dispersion of BOD5 and improved DO compared to the 0% pollutant removal scenario. Concentrations of the above water quality parameters also showed less variation from the 0% removal scenario by the wastewater treatment plant. The concentrations of BOD5 and DO in the removal scenarios of 0% and 80% allowed the Magdalena River to be classified as a source of acceptable quality according to Colombian regulations (BOD5 4 mg/l), possibly ensuring the preservation of flora and fauna.
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Substitution by Mass and Volume of a Natural Aggregate with Recycled Concrete Aggregate in an Asphalt Mixture

Hugo Alexander Rondón-Quintana, Carlos Alfonso Zafra-Mejía and Juan Carlos Ruge-Cárdenas.
International Journal of Advanced Science and Technology. Vol. 29, No. 4, (2020), pp.9804 – 9808

The foregoing article shows a study that had the main goal of evaluating the influence effect of substituting by mass and volume, natural aggregate (NA) of a hot mix asphalt (HMA) with recycled concrete aggregate (RCA). It specifically seeks to evaluate the influence this has on design, volumetric composition of mix and on mechanical resistance under monotonic load evaluated through the Marshall test. A better response can be observed in mixes in terms of resistance and optimum asphalt content (OAC) obtention when substitution of NA with RCA is done by volume. In terms of mix design, the HMA can use RCA as a substitute by mass of the coarse fraction of NA in roadways with low transit volume, increasing in 0.5% the OAC with relation to the control mix (100% NA), while the total substitution of aggregate would require an increase of 0.8%. When substituting the coarse fraction of NA with RCA by volume, the HMA mix can be used in roadways with high transit volumes by increasing the OAC in 0.3% with relation to the control mix, and the total aggregate substitution would require an increase of 0.5% in order to be used in roadways with low and medium transit volumes.
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Use of Recycled Concrete Aggregate as a Substitute of a Natural Aggregate by Mass and Volume within an Asphalt Concrete Base

Hugo Alexander Rondón-Quintana, Carlos Alfonso Zafra-Mejía and Juan Carlos Ruge-Cárdenas.
International Journal of Advanced Science and Technology Vol. 29, No. 4, (2020), pp. 10845–10850

Asphalt concrete bases (ACB) can be used as a base course or binder course in asphalt pavements. Generally, ACB aggregates are sourced from a natural origin, and these can be substituted by other construction waste material such as recycled concrete aggregate (RCA). The foregoing study substituted the coarse fraction and the entire natural aggregate (NA) of ACB with RCA. The influence of carrying out this substitution by mass or volume was evaluated within the mix design. For such purposes, the Marshall method was used. A better behavior was observed in mixes during the Marshall test when substitution is carried out by volume. In terms of mix design, ACB can use RCA as a substitute for its coarse fraction as well as the entire NA when dealing with roadways with low traffic volumes, increasing in 0.5% and 1.0% the asphalt content with relation to the control mix OAC (mix with 100% of NA as aggregate). By volume, RCA can be used in roadways with low or medium traffic volumes by increasing in 0.3% the asphalt content in relation to the control mix OAC when the coarse fraction is replaced, and in 0.6% when the entire NA is replaced.
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Measuring the liquid limit of soils using different fall-cone apparatuses: A statistical analysis

Juan Carlos Ruge, Fausto Molina-Gómez, Eliana Martínez-Rojas, Lenin Alexander Bulla-Cruz, Javier Camacho-Tauta. Measurement 152 (2020) 107352

The fall-cone test allows estimating the liquid limit of clayey soils in the laboratory. Due to its reliability and simplicity, several versions of the equipment have been developed around the world. The main vari- ations between these versions include differences in the weight and geometrical dimensions of the cones. This study explores the measuring of liquid limit using eight types of fall-cone apparatuses, including a proposed one with new configuration. A several number of tests on a natural soil from the lacustrine deposits of Bogotá and industrial Kaolin were conducted. The liquid limit results of all implemented cones in this study against values obtained in the same soils from the conventional percussion-cup (or Casagrande method) using a linear correlation model were compared. On the other hand, data was val- idated and interpreted by means of a statistical approach, which allowed estimating the repeatability of the methods. Conclusions focused on the similarities between the eight cone configurations and conven- tional percussion-cup test addressing the descriptive exploration, analysis of variance, two-by-two com- parisons and correlation between testing methods.
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Review of the use of nanomaterials in soils for construction of roads

Jhon Fredy Rincón-Morantes, Oscar Javier Reyes-Ortiz, Juan Carlos Ruge-Cardenas.
Respuestas, 25 (2) May-August 2020, pp. 213-223.

Nano materials are becoming more and more relevant in the construction of civil works, since they can be used as additions or additives to improve and stabilize asphalt concretes, hydraulic concretes, fine soils at the level of subgrade, sub-bases, bases and even for filters in water treatment. This article intends to collect the different experiences in the use of nano materials, in order to stabilize or improve the mechanical and geotechnical properties of soils used in road construction, especially what has to do with the manufacture of nano fibers for use in soils; finding that its use in the field of roads is to be investigated and developed with different types of solutions, as the most studied are the carbon nano fibers.
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Use of Thermally Treated Bentonite as Filler in Hot Mix Asphalt

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge-Cárdenas, Juan Gabriel Bastidas-Martínez,
Michael Yesid Velandia-Castelblanco, & Márcio Muniz de Farias.
J. Mater. Civ. Eng., 2020, 32(5): 04020070

Clays and clay minerals are widely used as raw materials in different industrial processes due to their abundance. Generally, in road construction projects, clays are considered waste materials because they have some undesirable engineering properties (e.g., plasticity and swelling properties). For this reason, this material is generally discarded in landfills or dumps. However, taking advantage of its abun- dance, this material could be used as a substitute for natural aggregates of hot mix asphalt (HMA) production as long as their undesirable properties are eliminated. In this study, a bentonite was thermally treated (subjected to high temperatures) in order to be used as replacement for the total filler content of a natural aggregate in HMA. X-ray diffractometry (XRD), X-ray fluorescence (XRF), Atterberg limits, and free swelling index tests were carried out on bentonite (with and without thermal treatment). Marshall, indirect tensile strength (ITS) (under dry and wet conditions), resilient modulus, permanent deformation, resistance to fatigue, and Cantabro tests were carried out on HMA mixtures using thermally treated bentonite (BT) as filler. On all test results an ANOVA test was carried out. When BT replaced the total fraction of the natural filler, its resistance under monotonic load, stiffness under cyclic loading, and resistance to moisture damage increased remarkably. A similar resistance to fatigue and abrasion in the Cantabro test was observed. Based on the results obtained, BT could be considered a technically viable alternative as a substitute material for natural fillers in HMAs.
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Virtual modelling of stress paths CKoU and CKoD on collapsible porous clayey soils

Juan Carlos Ruge C, E. Martinez, S. Bañol, J. León, Fausto Molina-Gómez.
Rev. int. métodos numér. cálc. diseño ing. (2020). Vol. 36, (1), 3.

In geotechnical engineering one of the challenges is the soil characterization. Nevertheless, currently it exists computational tools, which permits estimate the soil behaviour from information obtained in the laboratory. This document addresses the numerical modelling of triaxial tests set with Ko consolidation during its shear stage by means of single element test tool. The work methodology was based on the stress paths comparison between lab data and numerical simulations with three different constitutive models: (i) Mohr-Coulomb, (ii) Cam-Clay Modified, (iii) Hypoplastic. Such stress paths were obtained in drained and undrained conditions. The soil material corresponds to a porous collapsible clay from Brasilia (Brazil). Results show the calibration of the parameters for each constitutive model. Besides, presents the stress-strain curves until achieving the critical state condition in the simulations. Finally, it was established the constitutive model that presents the best fitting to the real behaviour of this kind of material, under specific conditions for advanced triaxial tests.
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Analysis of the Creep and the Influence on the Modulus Improvement Factor (MIF) in Polyolefin Geocells Using the Stepped Isothermal Method

Juan Carlos Ruge, Julian Gonzalo Gomez, and Carlos Andres Moreno.
Chapter Book in Geopolymers and Other Geosynthetics. (2019)

The article shows the analysis of the behavior at long-term deformation of geocells for a set time period, due to its importance on the modulus improvement factor (MIF), which is considered in the design stage of a reinforced pavement structure with geocells. When inquiring into the research about the structural behavior that exists in the geocells, as well as the distribution of stresses that this generates, in order to determine how important the existence of a deformation in the geocell is. We proceeded with the sampling and execution of the test “modified stepped isothermal method (SIM) for geocells.” The test was carried out under the comparison of the materials and thicknesses of the sample, with the purpose to analyze the influence on the behavior of a pavement structure. The stresses gener- ated at the level of the granular subbase layer of a pavement are taken into account as load effects.
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Behavior of Hot-Mix Asphalt Containing Blast Furnace Slag as Aggregate: Evaluation by Mass and Volume Substitution

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge-Cárdenas and Márcio Muniz de Farias.
J. Mater. Civ. Eng., 2019, 31(2): 04018364

Significant amounts of blast furnace slag (BFS) are generated daily as by-product from iron and steel industries. This waste material usually has interesting physical properties and mineralogical and chemical composition, which can be useful as granular aggregate in the production of hot mix asphalt (HMA). In this study, an experimental program was designed to evaluate the effect on the resistance of a HMA due to the replacement (in mass and volume) of the coarse fraction of a natural aggregate (type limestone; LS) by a BFS. Total aggregate replacement was also evaluated. The mechanical properties were evaluated by carrying out the following tests: Marshall stability, indirect tensile strength (ITS), Cantabro abrasion, resilient modulus, permanent deformation, and fatigue resistance. Water sensitivity or moisture damage was evaluated by determining the ratio of indirect tensile strength (TSR) in wet and dry conditions. X-ray diffractometry (XRD), X-ray fluorescence (XRF) tests, and imaging processing in a scanning electron microscope (SEM) were carried out on particles of LS and BFS. The results revealed a remarkable enhancement in the properties of the HMA mixture when the coarse fraction of the LS was replaced in volume by BFS. When such a replacement was made in mass, the adhesive properties of the asphalt-aggregate system worsened. Total replacement of the LS led to unsatisfactory mechanical behavior.
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Partially saturation effect on fine sands and earth pressure in a sheetpile wall

Juan Carlos Ruge C, Fausto Molina-Gómez, J.G. Bastidas, R.P. Cunha, I.F. Otálvaro.
Rev. int. métodos numér. cálc. diseño ing. (2019). Vol. 35, (4), 48.

Generally, the effects of suction in fine sands can be evidenced by a stiffening of the material, as the capillary front advances in the granular skeleton. In geotechnical retention structures this effect can be translated in an increasing of earth pressure, which is not normally considered in geotechnical designs. This study analyzes the capillary effects by implementing a physical modelling in centrifuge and a numerical simulation, using different constitutive models that involve suction within the analysis. The modelling is based on a structure of retention in sheetpiles built on a real scale. Some factors that affect both physical and numerical modelling were taken into account and should be considered in the analysis of the results obtained and, in the comparisons, carried out by both methodologies. As a point of interest, numerical modelling showed less dispersion in the results obtained than physical modelling, these and other aspects are analyzed in the document
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Soil stabilization with lime and fly ash

Gerardo Parra Goméz, Juan Gabriel Bastidas Martinez & Juan Carlos Ruge Cárdenas.
978-1-7281-4746-8/19 ©2019 IEEE

This work was evaluated in the laboratory, the mechanical resistance under monotonic loads and the compression of several test bodies, by additions of lime and fly ash at 2%, 4%, 6% and 8%, based on the proctor test standard and the study soil (kaolin); prior to this, a characterization of the materials was made, and finally the objective was to determine the improvement of the soil through the comparisons, which refers to what is due to the best that is given to the best. Ash is not a significant improvement in the soil. In general, if a stabilization of a soil is required quickly, the data is published as a better option for soil improvement
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Assessment of groundwater level variations using multivariate statistical methods

Fausto Molina-Gómez, Lenin A. Bulla-Cruz, Luis Á. Moreno-Anselmi, Juan C. Ruge, and Carol Arévalo-Daza.
INGENIERÍA E INVESTIGACIÓN VOL. 39 NO. 1, APRIL - 2019 (36-42)

Fluctuation of groundwater level induces changes in pore-water pressure of soil. However, this variation is not considered for underground constructions. This article explores the application of a statistical method to evaluate the groundwater level variation in geotechnical designs. The methodology included: (i) data collection, (ii) statistic formulation, and (iii) statistic data analysis. We collected information from the technical studies of the project “Metro de Bogotá”, and selected four boreholes spanning 160 m, approximately, where the 1◦ de Mayo metro station will be built, in the south of the city. We used groundwater level readings reported by different piezometers for 30 days and data variance was assessed using a multivariate statistical method: analysis of repeated measures profiles. Results present a procedure to estimate the groundwater level fluctuation during a short monitoring period. We concluded that the analysis of repeated measures profiles allows estimating the groundwater level variation under a significance level 1-α.
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Determination the coefficients of San’s model, to calculate the percentage of removal flocculent particles with three coagulants types

Diego Alejandro Pulgarín, Felipe Santamaría-Álzate, Juan Carlos Ruge & Oscar Iván Orduz.
Revista DYNA, 86(210), pp. 131-136, July - September, 2019.

This study calculated coefficients for the model elaborated by Hasan Ali San in 1989 based on the percentage of flocculated particles removed by three coagulants commonly used for water purification. The coagulants used were type A aluminum sulfate, type B aluminum sulfate and ferric chloride. An experiment was designed to study water with initial turbidity between 25 and 30 Nephelometric Turbidity Units (NTU). The experiment consisted of filling a sedimentation column with water and colloid particles which were agitated rapidly and then slowly with compressed air. This allowed the percentage of particles removed from the remaining turbidity to be determined at different times and different depths by measuring sedimentation of the flocculated particles. Once percentages of material removed had been calculated, an isoconcentration graph was elaborated and multiple linear regression was used to determine the coefficients of the model proposed by San.
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Evaluation of Hot-Mix Asphalt Containing Portland Cement Treated Blast Furnace Slag

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge & Juan Gabriel Bastidas Martinez.
Archives of Civil Engineering. Vol LXV Issue 2 (2019)

Iron production’s waste materials include significant quantities of blast furnace slag (BFS) which could potentially be used as a substitute for natural aggregates in hot mix asphalt (HMA) used in highway projects. Although many of properties of slag are interesting, its porosity and absorption rate would lead to greater consumption of asphalt. For this study, a Portland cement (PC) paste was used to reduce the porosity of a BFS. This PC treated BFS (called BFS-C) was then used in an HMA to replace the coarse fraction of a natural aggregate. Marshall, Indirect Tensile Strength (ITS), resilient modulus and Cantabro tests were then carried out on different HMA mixtures that included BFS-C. Using BFS-C, HMA’s resistance under monotonic loading, stiffness under cyclic loading, and resistance to moisture damage increased remarkably. In addition, the Cantabro abrasion resistance of BFS-C improved was better than that of the HMA mixture produced with untreated BFS.
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Analysis of numerical simulations on triaxial compression tests using different constitutive models of the soil behaviour

M C Olarte and J C Ruge
5th International Week of Science, Technology & Innovation. J. Phys.: Conf. Ser. 1388 012015 (2019 )

To reproduce in an accurate way by artificial methods the real behaviour of the soil is extremely complicated, given the intrinsic heterogeneity of the soil and the innumerable external factors that affect its mechanical-hydraulic response. At present, there are several constitutive models, both traditional and modern, that attempt to simulate the possible stress paths that a geomaterial can undergoes. Within the practical engineering the most used model has been Mohr-Coulomb, which shows an elastic-perfectly plastic response. However, the soil is far from exhibiting a behavioursimilar to that shown in this model. Modern constitutive laws can simulate in a more appropriate way the non-linear behaviour of the soil. However, they use several parameters that increase the complexity of the models. The objective of these constitutive models is none other than to extrapolate its mathematical formulation to the global behaviour of geotechnical structures. Before adjusting the parameters that should be used in the numerical modelling of real geotechnical problems, it is necessary to understand the behaviour at the elementary level (experimental) of the constitutive model. Normally this process is called calibration of parameters. In this work, the numerical results of triaxial compression tests for a typical normally consolidated soil are shown. Various constitutive models are used, which reveal different stress paths, for which the dispersion in the obtained results is considered.
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Artificial modelling of unsaturated tests considering the suction control on porous collapsible clay

J C Ruge
5th IMRMPT. J. Phys.: Conf. Ser. 1386 012116 (2019 )

Soils with a tendency to show phenomena of collapsibility generally have a susceptibility to be controlled by partial saturation, due to its structural configuration which reveal in some cases bonds of cementing minerals, that can be broken in process of wetting. This cementation is governed by the lateritic genesis, as well as for a microporal predominance. Laboratory tests that intend to reproduce the unsaturated condition, need a suction control to simulate properly the levels of stress required in the sample, according with the in-situ stresses presents in the soil mass. However, these tests are difficult to have access to given that they have a complicated assembly and can last several days (even months), due to the benefit in the resistance imposed by the suction on the soil. For this reason, it is extremely important to validate numerically by means of an appropriate constitutive law, at least at the laboratory level, the unsaturated response of a material. In this case a collapsible porous clay of lateritic origin, cause the high dependency of specialized laboratory tests can lead to non-necessaries delayed researches, that can impact in the economy of any project. In this research, an emphasis is placed on the numerical simulation of partially saturated tests through a hypoplastic constitutive model that involves suction in its mathematical formulation. The results are oriented to show the dependence of the suction with the shear strength of the material.
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Mineralogical, microstructural and porosimetry analysis in three different clayey soils

J C Ruge, X Palacios, F Molina-Gómez, and J P Rojas Suárez.
5th International Week of Science, Technology & Innovation (2019).

Diffraction, scanning electron microscope and helium porosimetry techniques have been shown to be suitable for obtaining physical and mineralogical properties in soil samples. The X-ray fluorescence spectroscopy allows obtaining the elemental composition of the sample, while the X-ray diffraction technique permits obtaining a qualitative and quantitative composition of the soil minerals. On the other hand, scanning electron microscope shows the microstructure of the soil and the helium porosimetry measures the pore size, volume, distribution, density and other porosity-related characteristics of the material. This document presents the characterisation of three different clayey soils by an experimental plan that included mineralogical, microstructural and porosimetric tests. The soils used were bentonite, kaolin and a natural clay retrieved near to Bogot ́a city, Colombia. Results obtained from this study allow providing a better understanding of soil behaviour, which traditional mechanical tests do not explain.
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Thixotropic behaviour study of clayey soils from the lacustrine deposits of Bogotá high plateau

J C Ruge, F Molina-Gómez, and J P Rojas Suárez.
5th IMRMPT. Journal of Physics: Conference Series 1386 (2019) 012050.

Thixotropy is a distinctively rheological (time-dependent) phenomenon, which is found in many complex materials, especially colloidal systems as fine-grained soils. Clays are materials that can recover their initial strength after remoulding. The estimation of such recovering allows optimising the designs of geotechnical structures and then reducing the construction costs. This paper presents the results of a study that evaluates the thixotropy phenomenon of clayey soils. The work methodology involved an experimental plan composed of five phases: (i) extraction of samples; (ii) physical and mechanical characterisation of the undisturbed samples; (iii) remoulding of samples after testing; (iv) storage of remoulded samples; and (v) evaluation of undrained shear strength recovering for 0, 15, 30, and 60 days after remoulding. Undisturbed samples were collected using Shelby tube from the municipality of Madrid, near Bogot ́a, in Colombia. Results were analysed in terms of sensitivity degree because this parameter allows estimating the shear strength recovering. Findings show that clayey soils from lacustrine deposits of Bogot ́a high plateau do not loss completely all of their original mechanical properties after remoulding and exhibit a medium sensitive behaviour. Conclusions indicate there is a recovering of undrained shear strength along the time, in which the samples will recover their original state about one year after remoulding.
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Measurement of hydraulic conductivity under horizontal paths in granular soils

Maria Fernanda García, Camilo Andres Aldana, Allex Fabrizio Lopez, Juan Carlos Ruge-C, Eliana Martinez-Rojas.
Respuestas, 24 (3), September - December 2019, pp. 92-101.

In geotechnical structures, the permeability-dependent stability analysis is generally evaluated under vertical trajectories, because most permeameters are configured so that the water passes through the porous medium in this way. However, it is clear from the physical point of view that water can flow along different paths, including preferential ways that can include horizontal trajectories, parallel to the deposit of the stratum. The foregoing implies that both the vertical and horizontal component of the hydraulic conductivity or permeability coefficient must be estimated for a given stratum. The current research aims to explore possibilities for measuring the coefficient of permeability in horizontal trajectories, on granular soils, under a constant condition of relative density. For this purpose, a special chamber attached to a constant head permeameter was designed and constructed, which allows to measure the permeability in conditions of horizontal flow parallel to the soil layers. The proposed camera also admits the estimation of the permeability coefficient by combining stratifications of different granular soils, where the trajectories are not perfectly horizontal, but have diagonal paths. The results are compared with data obtained by conventional vertical flow permeameters, in order to check the difference in the measurements considering both situations in the samples. As a conclusion, it is important to report that there is evidently a difference in the permeability coefficients measured under different trajectories
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Blast Furnace Slag as a Substitute for the Fine Fraction of Aggregates in an Asphalt Mixture

Hugo Alexander Rondón-Quintana, Juan Carlos Ruge-Cárdenas, Daniel Francisco Patino-Sánchez,
Hermes Ariel Vacca-Gamez, Fredy Alberto Reyes-Lizcano, & Márcio Muñiz de Farias.
J. Mater. Civ. Eng., 2018, 30(10): 04018244.

Blast furnace slags (BFS) have interesting physical properties and chemical compositions for the production of mastics in asphalt mixtures. However, most of the studies conducted on this material and their applications in asphalt mixtures have been as substitutes for the coarse fraction of natural aggregates (NGA). In the present study, an experimental program was devised to evaluate the effect on the resistance of a hot mix asphalt (HMA), due to the replacement of fine fraction of a NGA by a BFS. The mechanical properties investigated were indirect tensile strengths, resilient modulus, permanent deformation, resistance to fatigue, and moisture damage. Analysis of variance (ANOVA) tests were performed to verify or reject the null hypothesis that the results are statically equal to those of the reference mixture. X-ray diffrac- tometry (XRD) and X-ray fluorescence (XRF) tests were carried out on particles of BFS and NGA. Additionally, the samples were subjected to imaging processing in a scanning electron microscope (SEM). Characterization tests (viscosity, softening point, penetration, and indirect tension) were performed on mixtures made of fine particles (NGA and BFS) and asphalt. The BFS used as fine aggregate tends to generate, in conjunction with asphalt, a material with improved properties of resistance under monotonic and dynamic load.
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Characterization of blast furnace slag for road projects

H. Rondón, W. Fernández, D. Patiño, J. Ruge, H. Vacca, F. Reyes.
Revista Ingeniería de Construcción. Vol 33 No1 2018.

The present study evaluated the potential use of Blast Furnace Slag (BFS) as forming material of untreated granular layers in pavement (e.g. base, subbase and subgrade), and as stone aggregate in the manufacture of asphalt mixtures. For that purpose, tests of characterization, X-ray diffractometry (XRD), X-ray fluorescence (XRF) and imaging in a scanning electron microscope (SEM) were executed on the BFS. As a general conclusion is reported that the BFS can be used in the formation of unbound granular layers of subbase. As granular base material, its use would be recommended on roads with low traffic volumes or with thick asphalt layers and as a selected material, in tertiary roads that support light traffic. In the case of HMA is not recommended to use the coarse fraction of the BFS as a stone aggregate. However, the obtained results indicate that the fine fraction shows good characteristics to be used in the production of the mastic of such mixtures.
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Factors influencing the correct positioning of offshore jack up rigs

Juan Carlos Ruge, Jorge A. Navarro and Fabio Malagon.
Interciencia; Tomo 43, N.º 2, (Feb 2018): 120-124.

The positioning of offshore self-elevating (jack-up) type platforms involves the development of a series of demanding activities and processes. Among them are included the analysis of Geohazards that may be present above and below sea level, stability analysis and the historical oceanography study of the area of interest. The integration of this information will allow the selection of the best site for the positioning of the jack-up rig. The paper describes the methodology for the analysis of the stability in these type of platforms, which comprises the following stages: site survey analysis, geotechnical analysis and oceanographic analysis, in the same way as the activities that are embedded in each of them were established. They will allow to study and to evaluate present conditions on and under the seabed, identifying the main risks that may represent unsafe conditions for the positioning and operation of the platform. Finally, the analysis of a particular case of a typical study in the Colombian Caribbean Sea is carried in a conceptual manner; in this case a specific methodology is applied and the integration of the information obtained in each of the project stages results in the application of an evaluation and identification of the risks presented in the study area, so as to select the best place for the correct positioning of the platform.
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Reinforced concrete with synthetic fibers (PET+PP) for rigid pavement structures

Diego Alexander Torres, Juan Gabriel Bastidas & Juan Carlos Ruge Cárdenas.
IEEE. 78-1-5386-8131-2/18 ©2018

This work evaluated in the laboratory, the mechanical resistance at 28 days under monotonic load that undergoes a hydraulic concrete when adding contents in weight of 0%, 2%, 3% and 4% of synthetic fibers of Terephthalate Polyethylene (PET) and Polypropylene (PP) on the total weight of the aggregates. From the results obtained, it is concluded that the residual stress increases as a function of the content of synthetic fiber compared to conventional concrete or with 0% addition of synthetic fibers. The presence of fibers can contribute to the reduction of contraction cracks generated in the first 24 hours of concrete hardening and to the increase in ductility after rupture. The technique of the addition of synthetic fibers in concrete is technically feasible by obtaining a reduction in the routine and periodic maintenance of rigid paving slabs.
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The geological history analysis of the friction angle in transported soils and their importance in the bearing capacity of shallow foundations

C. Mendoza, J. Ruge and B. Caicedo.
Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería (2018).

This work shows the variability of the friction angle based on the geological history, over the bearing capacity of shallow foundations. This study was developed through the generation of random fields of friction angle using the matrix decomposition technique for a self-correlated lognormal distribution. In addition, to recreate the geological history, the anisotropic random fields were created using the rotation matrix with angles of 0, 45 and 90 degrees. Subsequently, these random fields were implemented in a finite element model of a continuous footing. A linear elastoplastic constitutive model was selected to represent stress-strain soil behavior together with the Mohr-Coulomb failure criteria. This last work was done in order to understand the influence of geological history and the variability of the friction angle in the bearing capacity of shallow foundations. Results include the weight of the variability of the friction angle in the bearing capacity and the influence of the dip over the friction angle and the bearing capacity.
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Analysis of the undrained shear strength through the standard Penetration Test with Torque (Spt-T)

J. C. Ruge, C. C. Mendoza, J. E. Colmenares, R. P. Cunha, I. F. Otalvaro.
International Journal of GEOMATE, Jan., 2018 Vol.14, Issue 41, pp.102-110.

Although in situ tests are very useful for obtaining data on the strength and deformation of a geomaterial, some of these tests have been criticized because of their limitations for identifying certain parameters. This paper presents research into a hitherto little used test here in Colombia, the SPT-T (Standard Penetration Test + Torque). This test combines the advantages of the Standard Penetration Test (SPT) and the Vane Shear Test (VST) to obtain a soil’s lateral friction and to correlate its classification and structure by means of the relationship between the NSPT and the torque applied. This study reaffirms the dependent relation between T/NSPT and soil structure found elsewhere in the world and investigates whether parameters governing the undrained condition of soil may be correlated with T/NSPT. Conceptually, a relationship between undrained soil conditions and the way the test is conducted is evidenced. For this reason, this research is an initial approach which open the door to continuing phases of research that may be able to develop appropriate correlations between undrained strengths of soft soils and the T/NSPT parameter used in analyses of this test.
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Shear modulus of mining tailings from resonant column tests

Eliana Martínez-Rojas, Fausto Molina-Gómez & Juan Carlos Ruge.
Revista DYNA, 85(205), pp. 310-318, June, 2018.

This article presents the results of seventy-two resonant column tests performed in two types of materials from the waste deposits of the Riotinto mines (Huelva – Spain). Methodology test included different conditions of effective consolidation pressure and torsional excitation level. The equipment used was a fixed-free resonant-column system. The effective consolidation pressures were established within a range between 50 - 300 kPa and the torsional excitations were equal to 0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 V. It was found that such test combinations lead to angular deformations between 0.003% and 0.148%. The results indicate that it is possible to establish simple empirical functions of the stiffness module as a function of the angular deformation and the effective consolidation pressure.
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Variabilidad espacial un suelo arcilloso del sector Sabana Centro para la confiabilidad de asentamientos por consolidación primaria: caso de estudio Campus Nueva Granada

Fausto Molina-Gómez, Juan Carlos Ruge y Javier Camacho-Tauta.
Ingeniería y Ciencia. Vol. 14, no. 27, pp. 179–205, enero-junio. 2018.

El objetivo de este artículo es presentar un estudio de confiabilidad de los parámetros de consolidación de un suelo arcilloso de la Sabana de Bogo- tá. La metodología de trabajo comprendió la extracción de muestras de arcillas inalteradas y la ejecución de un plan experimental de laboratorio que incluyó treinta ensayos edométricos. Además, se estimaron las distri- buciones de probabilidad de los parámetros de consolidación del suelo de la Sabana de Bogotá. Los resultados permitieron obtener la variabilidad de las propiedades de compresibilidad de dichos materiales. Por otra parte, se realizaron simulaciones de Monte Carlo para estimar las curvas de confiabilidad de asentamientos. Se encontró que la magnitud de los asen- tamientos en los suelos arcillosos de la Sabana de Bogotá se ven afectados por la variabilidad espacial de las propiedades de compresibilidad de este tipo de suelo.
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Aspectos que condicionan las modelaciones físicas en la predicción del comportamiento de estructuras geotécnicas reales

Camilo Andrés Fino Vela, Diego Andrés Lozano & Juan Carlos Ruge.
Brújula Semilleros De Investigación, 6(11), 35–42. 2018.

El uso de modelos reducidos a escala para reproducir el comportamiento de estructuras geotécnicas es la técnica con mayor aceptación hoy en día para modelar apropiadamente un problema geotécnico. La metodología más completa para modelar adecuadamente este tipo de escenarios es la centrífuga geotécnica, la cual permite ensamblar modelos reducidos a la escala necesaria e induce en el modelo un campo de gravedad proporcional a la escala seleccionada. De acuerdo con leyes de escalamiento establecidas, diferentes cantidades pueden ser extrapoladas desde el modelo reducido a una estructura a escala real. No obstante, varios aspectos que deben ser considerados en detalle inciden en los resultados, de manera que se deben analizar de manera concienzuda para que la dispersión de resultados entre las mediciones y lo previsto sea lo menor posible, o, en caso contrario, se pueda identificar con confiabilidad cuál fue el aspecto que más influyó en la alta dispersión de los resultados. Esta investigación describe estos efectos con exactitud con el fin de que sean tenidos en cuenta cuando se realice este tipo de análisis de predicción en estructuras geotécnicas.
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Numerical Simulations of K0 Triaxial Tests on Collapsible Porous Clay

J.C. Ruge, A. López, F.A. Molina-Gómez, R.P da Cunha and J.E. Colmenares.
Geotechnical Engineering Journal of the SEAGS & AGSSEA Vol. 49 No. 3 September 2018

This paper addresses numerical simulations of K0 triaxial tests performed using a single element program. The methodology was based on construction of numerical models with three different constitutive models in order to represent the soil behaviour during stress path states. The constitutive models used were (i) the Mohr-Coulomb, (ii) the Cam-Clay, and (iii) a hypoplastic model. The material used was a collapsible porous Brazilian clay. The values obtained were compared and calibrated with experimental data. Results show that it is possible to assess soil behaviour via a single element program and that triaxial K0 stress path tests can be simulated with numerical methods. Results show that it is possible to replicate and calibrate soil behaviour under zero lateral displacement using computational tools.
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Class A prediction of a retaining structure made by a pile curtain wall executed on a tropical soil

Juan Carlos Ruge, Renato P. Cunha, Julio E. Colmenares & Cristhian C. Mendoza.
Revista DYNA, 84(202), pp. 278-288, September, 2017.

Some retaining structures can be designed on a temporary basis, in accordance to the geotechnical design and a predefined construction plan. Off course this may not be valid elsewhere, but in Brasília, where residual and laterized soils do prevail, best mechanical resistances are obtained in the porous clay setrata along the dry season. That means, it is controlled by soil ́s suction, i.e. soil behavior presents a dependency on the unsaturated response of the medium. In numerical terms, to predict the soil-structure behavior it is necessary to include the atmosphere-soil interaction in the computational tool, using a hypoplastic model. The paper thus details on this aspect and on the numerical simulations of an existing retaining structure founded in the tropical soil of Brasília. The structure was monitored in terms of displacement, along local dry and wet seasons, and was simulated by a constitutive law calibrated by means of unsaturated laboratory tests.
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Numerical Simulations of Ko Triaxial Tests on Collapsible Porous Clay Samples

Juan Carlos Ruge C.
Memorias: VII CONGRESO DE INVESTIGACIÓN ES ING. GEOTECNIA E HIDRÁULICA PARA LA CONSTRUCCIÓN DE UN MEJOR PAÍS. p. 4-11 (2017).

En esta ponencia, se muestran los resultados obtenidos mediante las simulaciones realizadas a ensayos de compresión triaxial de tipo K0, usando modelos constitutivos modernos y tradicionales, los cuales fueron la base para el cálculo de los parámetros de cada uno de los modelos. La principal premisa para el desarrollo de este documento se basó en considerar bajo qué condiciones los modelos simularían mejor el comportamiento del suelo de los ensayos ejecutados, cual de ellos podría tener un mejor desempeño, que características de cada uno de los modelos permitirían obtener un mayor ajuste frente a lo obtenido en lo experimental. Por lo anterior, se realizaron las comparaciones frente a lo arrojado por cada uno de los modelos estudiados, para finalmente concluir que el mayor ajuste de los modelos depende de las condiciones bajo las cuales fueron ensayadas las muestras. Para las simulaciones se implementó un programa “Element Test” conocido como Incremental Driver.
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Modelación numérica de edificio modular de contenedores marítimos ISO de 20 pies

Alejandro Santoyo, Juan Carlos Ruge & Daniel Alberto Zuluaga Astudillo.
Revista Ingenieros Militares. Número. 12, p. 10-18. (2017).

Si bien en el panorama actual de la ingeniería y la arquitectura, las estructuras prefabricadas basadas en la reutilización de contenedores ISO ya han adquirido gran popularidad a lo largo de todo el planeta, se ha evidenciado que su uso se limita principalmente a los terrenos estables desde el punto de vista sismo resistente y con suelos de fundación de buena capacidad portante. Debido a que el acero presenta una gran resistencia a solicitaciones de carga, a flexión, flexo-tracción y flexo- compresión, es necesario entender por lo menos en el concepto numérico el comportamiento estructural de estas estructuras modulares. Para tener un panorama más claro sobre la estabilidad estructural de los edificios modulares de contenedores se modelo de manera numérica, un edificio de 5 niveles de altura y con distribución de 4 contenedores de 20 pies de longitud por piso, así mismo se añadieron perfiles metálicos junto a cada elemento estructural predominante, es decir vigas y columnas, los cuales a su vez se amarraron a través de cables de acero a 6 pilotes esquineros que anclan a esta estructura en general al terreno y por otro lado para un modelo simplificado se agregaron en las dos caras más delgadas en los extremos del edificio, unos perfiles cuadrados de manera inclinada y a 45o unidos con una hipotética soldadura típica manejada por el software manejado –SAP 2000 v.15. Se compararon estos resultados de momento y deformaciones con los recibidos al aplicar cargas vivas, muertas, fuerzas de sismo y de viento a un edificio de iguales dimensiones con contenedores simplemente apoyados un sobre otro y de esta manera, algo similar a lo que ocurre con las construcciones de similares características en el viejo continente.
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Influence of Structure in Bearing Capacity of Shallow Foundations in Tropical Soils

Cristhian C. Mendoza, Juan Carlos Ruge and B. Caicedo.
Electronic Journal of Geotechnical Engineering, 2016 (21.11), pp 4223-4236.

This paper uses the Finite Element Method together with randomness and a hypoplastic constitutive model considering structure. Using these elements, Monte Carlo simulations of a loading test in a footing were performed, by varying the parameters of soil structure (parameters of constitutive model). This was performed with the objective of understanding the behaviour of the bearing capacity in shallow foundations over tropical soils with structure. Furthermore, the model considered the variability of the depth of the foundation. Tropical soils are special because they present high void ratios (e values up to 2) and high permeability (10-3 - 10-4 cm/s). To simulate the soil structuration, a hypoplastic model for fine soils (Mašín, 2013) is implemented in the finite element program Abaqus. This model takes into account the effect of soil structuration. Among the most important results of the simulations, it was observed that soil cementation caused a decrease in the bearing capacity when this study measured the importance of footing depth in the bearing capacity.
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Analysis of the Mechanical Behavior on Reconstituted Kaolinitic Samples with an Epoxy Core

Daniela Toro Rojas, Juan Carlos Ruge and Renato P. da Cunha
Electronic Journal of Geotechnical Engineering, 2016 (21.19), pp 6521-6534.

Many of the geotechnical problems currently addressed by designers and/or researchers, present complexities related with the scope of different states of stress and strain levels, in diverse points of the analyzed geotechnical structure. Similarly, some of these problems also show that some part in the geotechnical structure, especially when dealing with excavations, undergoes tensile stress paths. The global analysis of a structure tends to be complex, given the fact that the soil is a material that poses a variable behavior, sometimes erratic, and a low tensile and flexural strength. One of the current challenges of geomaterial engineering is to give the soil properties that it does not have or in which it has mechanical deficiencies, by the addition or inclusion of alternative materials. One of the most used techniques to reinforce the soil when subjected to tensional stress is called soil-nailing. This methodology is constituted by anchors that are responsible for the stabilization of slopes through steel bars fixed with cement grouts; whose interaction with the surrounding soil is produced throughout the length of the bar. However, other materials could accomplish the function of this set, such as epoxy resins, a polymeric material that is characterized among other things by having an acceptable mechanical behavior when subjected to diverse loads. Therefore, together with the soil they form a different alternative to the ordinary anchors soil-nailing type. In this article the behavior of a reconstituted kaolinitic soil and its interaction with a core of epoxy resin is analyzed, in order to determine quantitatively at a small scale the adherence in the interface of these materials and thus verify their capacity as eventual stabilization system.
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Efecto del agua sobre el asfalto y su posible influencia en el daño por humedad en una mezcla asfáltica porosa

Hugo Alexander Rondón Quintana, Juan Carlos Ruge Cárdenas, Luis Ángel Moreno Anselmi.
Ingeniare. Revista chilena de ingeniería, vol. 24 No 4, 2016, pp. 558-569

Uno de los principales mecanismos de daño de mezclas asfálticas en servicio es el daño por humedad. Este fenómeno ocurre principalmente cuando se separa el ligante asfáltico del agregado pétreo debido a la presencia de agua (stripping). Diversos estudios han sido ejecutados con el fin de intentar entender el fenómeno. A pesar del alto número de investigaciones realizadas, las causas que lo generan no han sido totalmente entendidas e identificadas. El artículo presenta los resultados de un estudio experimental, ejecutado con el fin de evaluar la influencia que tiene el ligante asfáltico sobre el fenómeno, debido solo al efecto del agua. Sobre dos cementos asfálticos - CA (CA 80-100 y CA 60-70), se midió el cambio que experimentaron algunas de sus propiedades físicas (punto de ablandamiento - ASTM D36, viscosidad absoluta - ASTM D-2171, viscosidad a 135 oC - AASHTO T-316 y penetración - ASTM D-5), químicas (ensayo SARA - ASTM D-4124) y reológicas (AASHTO T 315-05) cuando fueron sumergidos en agua durante 12 a 17 meses. Ensayos de resistencia bajo carga monotónica (Marshall, AASHTO T 245-97, 04) y de desgaste por abrasión (Cántabro, NLT 352/86) fueron ejecutados sobre una mezcla asfáltica porosa sumergida en agua durante 17 meses, y sobre la misma mezcla, pero fabricada con los asfaltos sumergidos en agua. Como conclusión general se reporta que los asfaltos en presencia de agua experimentan dentro de la mezcla contracción del ligante asfáltico, lo que podría ser una de las causas que generen el fenómeno de daño por humedad.
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Análisis de las correlaciones existentes del ángulo de fricción efectivo para suelos del piedemonte oriental de Bogotá usando ensayos in situ

July E. Carmona-Álvarez & Juan C. Ruge-Cárdenas.
Tecno Lógicas. Vol. 18, No. 35, julio-diciembre de 2015, pp. 93-104.

Estimar el ángulo de fricción efectivo del suelo a partir de ensayos in situ es una tarea complicada debido a las altas tasas de deformación existentes en este tipo de ensayos, que tienden a ser demasiado invasivos y perturban las vecindades de la profundidad del ensayo y aún la muestra que eventualmente se toma en el sitio. Así mismo, la mayoría de correlaciones encontradas en la literatura actual, para obtener el ángulo de fricción efectivo, usando ensayos de campo han sido desarrolladas para suelos de otras latitudes, por tal razón al ser implementadas en suelos tropicales presentan alta dispersión, cuando se desea comparar los valores de parámetros de campo, con los resultados reales obtenidos en el laboratorio. Esta investigación busca mediante el uso de ensayos in situ, definir por medio de análisis de diferentes correlaciones, cuál de estas se ajusta mejor a las condiciones propias de suelos del piedemonte de la ciudad de Bogotá, la cual se considera la problemática primordial a resolver en el artículo. Para el presente estudio serán utilizados datos provenientes del SPT - Standard Penetration Test (de amplio uso en Colombia) y SPT-T Standard Penetration Test + Torque (nunca antes llevado a cabo en el país), realizados teniendo en cuenta la normativa acorde para cada ensayo. Considerando que para el SPT-T no existe norma local que rija este tipo de ensayos. Las correcciones por procedimientos de campo de los ensayos que se implementaron fueron realizadas por confinamiento efectivo y transferencia de energía del martillo golpeador, ya que en el estado del arte del tema son definidos como los que influyen de manera directa en la confiabilidad de los resultados. Los resultados finales muestran la tendencia de cada una de las metodologías usadas para obtener la correlación, en relación con el valor real del ángulo de fricción efectivo, obtenido de ensayos de laboratorio.
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Condiciones técnicas para la ejecución de infraestructuras de movilidad y transporte en Bogotá

Hernán Antonio González-Urrego, Juan Carlos Ruge-Cárdenas, Carles Labraña-De Miguel. Respuestas. 2014; 19(1):39-49.

Colombia está en un proceso de crecimiento económico acelerado, debido al gran atractivo geopolítico con el que cuenta y su excelente potencial de explotación de recursos naturales. Sin embargo existe un déficit importante de infraestructuras para la movilidad y transporte en los ámbitos rural y urbano, que afecta directamente dichos procesos económicos, en la improductividad ocasionada por las ineficientes infraestructuras de movilidad terrestre que comunican al país. En el ámbito metropolitano, la situación llega a ser crítica como ocurre en Bogotá, ciudad para la cual se han realizado innumerables estudios en ejecución de redes de transporte masivo de pasajeros que no son técnicamente factibles debido a que desconocen toda la complejidad que implica su territorio. Objetivo: Este texto introductorio a otros más específicos de los mismos autores, contiene los parámetros básicos a veces pasados por alto en los estudios de factibilidad técnica, con el objetivo de ponerlos en conocimiento de todos los posibles agentes (como también de los futuros usuarios) que participan en la realización de estudios de construcción en infraestructuras para la movilidad y el transporte con énfasis en Bogotá, aunque algunos de sus contenidos también pueden servir de referente para otras ciudades. Método: Mediante un análisis exhaustivo basado principalmente en información secundaria (fotografías aéreas, imágenes de satélite, fotografías del sitio, microzonificación sísmica, etc...) y experiencias en otras latitudes, se identificaron sitios neurálgicos de la ciudad de Bogotá con problemas de movilidad y que tuvieran un corredor ferroviario existente, para la implantación de un posible futuro Sistema Integrado de Transportes haciendo uso de diferentes tipologías de redes de conexión, a la luz de las necesidades de Bogotá y su conexión regional en el corto (5 a 8 años), mediano (5 a 10 años) y largo plazo (15 a 30 años) con una proyección de 30 años. Resultados: De acuerdo a diferentes variables que controlan aspectos constructivos de la ciudad, como la complejidad geotécnica, gestión de cultura, recursos, tecnología de construcción, entre otros, se logró de manera conceptual diseñar diferentes alternativas constructivas para infraestructuras de movilidad y transporte considerando los aspectos ya mencionados. Conclusiones: El planeamiento urbano de la ciudad respecto al mejoramiento de la movilidad y el transporte, depende principalmente de dos vertientes, el impacto en la calidad de vida de los usuarios (influenciada por la actividad social y económica) y la articulación con la propuesta de transporte modal de Bogotá.
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Modelación virtual de trayectorias de esfuerzos CKoU - CKoD en arcillas porosas colapsables

Hernán Antonio González-Urrego, Juan Carlos Ruge-Cárdenas, Carles Labraña-De Miguel. Respuestas. 2014; 19(1):39-49.

Colombia está en un proceso de crecimiento económico acelerado, debido al gran atractivo geopolítico con el que cuenta y su excelente potencial de explotación de recursos naturales. Sin embargo existe un déficit importante de infraestructuras para la movilidad y transporte en los ámbitos rural y urbano, que afecta directamente dichos procesos económicos, en la improductividad ocasionada por las ineficientes infraestructuras de movilidad terrestre que comunican al país. En el ámbito metropolitano, la situación llega a ser crítica como ocurre en Bogotá, ciudad para la cual se han realizado innumerables estudios en ejecución de redes de transporte masivo de pasajeros que no son técnicamente factibles debido a que desconocen toda la complejidad que implica su territorio. Objetivo: Este texto introductorio a otros más específicos de los mismos autores, contiene los parámetros básicos a veces pasados por alto en los estudios de factibilidad técnica, con el objetivo de ponerlos en conocimiento de todos los posibles agentes (como también de los futuros usuarios) que participan en la realización de estudios de construcción en infraestructuras para la movilidad y el transporte con énfasis en Bogotá, aunque algunos de sus contenidos también pueden servir de referente para otras ciudades. Método: Mediante un análisis exhaustivo basado principalmente en información secundaria (fotografías aéreas, imágenes de satélite, fotografías del sitio, microzonificación sísmica, etc...) y experiencias en otras latitudes, se identificaron sitios neurálgicos de la ciudad de Bogotá con problemas de movilidad y que tuvieran un corredor ferroviario existente, para la implantación de un posible futuro Sistema Integrado de Transportes haciendo uso de diferentes tipologías de redes de conexión, a la luz de las necesidades de Bogotá y su conexión regional en el corto (5 a 8 años), mediano (5 a 10 años) y largo plazo (15 a 30 años) con una proyección de 30 años. Resultados: De acuerdo a diferentes variables que controlan aspectos constructivos de la ciudad, como la complejidad geotécnica, gestión de cultura, recursos, tecnología de construcción, entre otros, se logró de manera conceptual diseñar diferentes alternativas constructivas para infraestructuras de movilidad y transporte considerando los aspectos ya mencionados. Conclusiones: El planeamiento urbano de la ciudad respecto al mejoramiento de la movilidad y el transporte, depende principalmente de dos vertientes, el impacto en la calidad de vida de los usuarios (influenciada por la actividad social y económica) y la articulación con la propuesta de transporte modal de Bogotá.
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Simulación de pruebas de carga en pilotes usando un modelo constitutivo hipoplástico.

Ruge J.C., da Cunha R.P., Rondón H.
Revista EIA, 11(21):171–183, 2014.

En la ingeniería geotécnica uno de los mayores desafíos es la caracterización de del suelo. Sin embargo, en la actualidad existen herramientas computacionales que permiten estimar el comportamiento del suelo a partir de parámetros medidos en laboratorio. Este documento aborda la modelación numérica de la etapa de corte de una serie de ensayos triaxiales con consolidación Ko usando una herramienta tipo single element test. La metodología de trabajo se basó en la comparación de las trayectorias de esfuerzos entre datos de laboratorio y simulaciones numéricas, que fueron ejecutadas usando tres modelos constitutivos diferentes: (i) Mohr-Coulomb, (ii) Cam-Clay Modificado, (iii) Hipoplástico. Dichas trayectorias fueron obtenidas durante la etapa de corte en condiciones drenadas y no drenadas. El material de estudio corresponde a una arcilla porosa colapsable proveniente de la cuidad de Brasilia (Brasil). Los resultados exhiben el proceso de calibración de los parámetros de cada una de las leyes constitutivas para las simulaciones numéricas. Asimismo, estos muestran las curvas esfuerzo-deformación hasta alcanzar el estado crítico del suelo durante las simulaciones. Finalmente, se estableció el modelo constitutivo que presenta mejor ajuste al comportamiento real de este tipo de material bajo condiciones específicas de ensayos triaxiales avanzados.
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Resposta não saturada no comportamento de escavações suportadas mediante estruturas de contenção em estacas Unsaturated response in the behaviour of tied-back excavations using pile retention structures

J.C. Ruge; C.C. Mendoza; R.P. da Cunha; F. Alva.
XIV CONGRESO COLOMBIANO DE GEOTECNIA & IV CONGRESO SURAMERICANO DE INGENIEROS JÓVENES GEOTÉCNICOS. 2014.

Deformações ocorridas em estruturas de contenção executadas mediante cortinas de estacas podem ser seriamente influenciadas durante as sequencias executivas de construção, e ainda na vida útil da estrutura. Os principais aspectos que influenciam o comportamento são as precipitações, devido a que a chuva incide diretamente na saturação do solo, ocasionando variações na sucção de perfil. Este estudo visa como escopo principal simular de maneira artificial (modelagem numérica) uma escavação governada pela parcial saturação do solo, baseada no método dos elementos finitos, usando um modelo constitutivo hipoplástico que considera a sucção como parâmetro essencial na análise, além o modelo computacional utilizado leva em conta a chuva diária durante o processo executivo da contenção, relacionada diretamente com as curvas de retenção da agua do material. No caso de projetos de contenções especificamente na cidade de Brasília, as variações de sucção vêm-se refletidas em mudanças dos deslocamentos das cortinas dependendo da época do ano na qual o processo executivo da contenção é adiantado.
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Una Mirada Probabilística al Concreto de Alta Resistencia

Cerón, S. Zaira A., & Ruge, C. Juan C., & Rodríguez, P. Álvaro E.
Revista Ingenio Magno, Enero - Diciembre 2014, Vol. 5 pp. 18-27.

Este artículo presenta el análisis probabilístico realizado a dos diseños de mezcla para concreto de alta resistencia como primer paso para obtener un modelo estadístico que logre expresar los resultados de una forma más útil y permita determinar la resistencia y la calidad potencial del concreto. El análisis de resultados del ensayo de resistencia a compresión del concreto se llevó a cabo mediante el uso de un software estadístico llamado SPSS, que a partir de las diferentes variables estadísticas permitió indagar si la distribución de frecuencias, correspondía a la distribución normal que sigue el concreto convencional. Los resultados obtenidos muestran la distribución o la tendencia de resistencia de cada uno de los diseños. El análisis cuantitativo evidencia que la variación de resistencia del concreto refleja con rigor la importancia que tiene conocer las propiedades de la mezcla de concreto y el proceso en los métodos de ensayo.
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Aplicação da estatística em resultados de ensaios conduzidos em centrífuga geotécnica

Juan Carlos Ruge Cárdenas, Juan Miguel Sanchez Durán, Renato Pinto Da Cunha, Cristhian Camilo Mendoza Bolaños.
Pre-til. No. 30. pp 85-94 (2014)

O artigo apresenta os resultados de uma modelagem física realizada em uma estrutura de contenção do tipo estaca prancha construída em Hochstetten (Alemanha). Os resultados fo-ram comparados com aqueles obtidos em campo. A modelagem física foi realizada a partir de uma centrífuga geotécnica e os resultados obtidos demonstram que estas ferramentas podem ser utilizadas para prever o comportamento de uma massa de solo em um problema geotécnico relacionado com estruturas de contenção. Esta análise foi complementada com uma avaliação estatística a fim de estimar com melhor representatividade os dados devido à dispersão nos ensaios em centrífuga.
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Estudio de sistema Placa-Pilote con micropilotes de refuerzo auto- perforante

Cristhian C. Mendoza; Renato Pinto da Cunha; Juan C. Ruge; Nina Silveira.
XIV CONGRESO COLOMBIANO DE GEOTECNIA & IV CONGRESO SURAMERICANO DE INGENIEROS JÓVENES GEOTÉCNICOS. 2014.

En la práctica normal de ingeniería de cimentaciones se cuenta con gran cantidad de tipos de micropilotes para ser usados en labores de construcción y rehabilitación de fundaciones. En este trabajo se propone el uso del micropilote tipo “Alluvial Anker” para rehabilitación de estructuras, sabiendo que en la actualidad este carece de estudios realizados en su comportamiento a nivel académico. Para realizar lo anterior se ejecutaron pruebas de carga con diferentes tipos de configuraciones de sistemas placa-pilote a escala real con y sin aporte de la zapata, en un campo experimental construido especialmente para este propósito. Como resultados se obtiene el aporte de la zapata existente al nuevo sistema integrado, después de la rehabilitación de la estructura existente, además se obtienen los porcentajes de distribución de la carga en cada una de las partes del sistema placa-pilote para cada una de las configuraciones utilizadas.
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Some contributions to the behavior of piled-rafts made up by self-drilling piles founded in a tropical soil of Brazil

Cristhian C. Mendoza; Renato Pinto da Cunha; Juan C. Ruge; A. Lizcano.
Electronic Journal of Geotechnical Engineering. Vol. 19 pp. 17181-17194. 2014.

This work presents the mechanical behavior of a piled-groups and piled-rafts constructed with self-drilling piles and founded in the “porous” clayey soil of the Federal District in Brazil. At a first moment, characterization test, field tests (Standard Penetration Test and Flat Dilatometer Test) and triaxial tests were applied to the soil deposit to obtain its mechanical behavior. The hypoplastic constitutive model that considers soil structure was tested to assess if the model can describe the clay behavior. Moreover, the mechanical behavior of the piled group and of the piled-raft foundation was validated by means of static load tests performed in the experimental field of a private foundation company in the region. By using the collected data, finite element simulations (FEM) were performed using the Abaqus software. The chosen model was implemented to describe the behavior of the soil in the Federal District. Simulated results allowed the establishment of the ultimate load of the foundation systems; the stresses generated and settlement mechanisms; and the contribution of the raft in the piled- raft systems. The results and their direct comparison allowed the generation of knowledge of academic and practical interest to those involved with the practical design, the construction or the investigation of such foundation systems.
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Propuesta de una plataforma de pruebas para el análisis de la interacción llanta-pavimento

Miguel Silva Gómez, Rubén Darío Hernández & Juan Carlos Ruge Cárdenas.
Revista Clepsidra 9(17):61-69. 2014

El presente documento muestra el análisis de los métodos para el estudio de la interacción llanta pavimento dentro de la contaminación auditiva, permitiendo diseñar la propuesta de un prototipo tipo tráiler según la norma ISO 11819-2. Este diseño consiste en la ubicación de cuatro micrófonos cerca de los ejes para adquirir las ondas sonoras que se generan entre el asfalto y las llantas del tráiler, obteniendo la medición de las propiedades acústicas en diferentes tipos de superficies. en la primera etapa del proyecto, se desarrolló el diseño inicial del tráiler con ayuda de la herramienta de software inventor®. Posteriormente, se desarrollo la instrumentación electrónica por medio del programa pro tools®, este sistema contiene una tarjeta de adquisición de audio para cuatro canales y micrófonos capacitivos, que permiten la obtención de las señales de audio características del montaje con el cual se pueden determinar el análisis de los datos y caracterizarlos con los niveles de ruido existentes.
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ANÁLISE DO COMPORTAMENTO DE CORTINA DE ESTACAS EXECUTADA EM SOLO POROSO METAESTÁVEL MEDIANTE O USO DE UM MODELO CONSTITUTIVO HIPOPLÁSTICO CONSIDERANDO A RESPOSTA NÃO SATURADA

Juan Carlos Ruge Cárdenas
Tesis de Doctorado en Geotecnia. Universidad de Brasialia. 2014

A pesquisa exposta a seguir apresenta um estudo do comportamento de cortinas de estacas justapostas assentes na argila porosa de Brasilia, para este fim foi avaliado o comportamento do solo mediante ensaios saturados e não saturados de resistência e deformabilidade, porosimétricos, mineralógicos, de armazenamento de água e estrutura microscópica. A contenção foi instrumentada obtendo dados de deslocamentos e tensões atuantes nos grampos visando ter o comportamento global da estrutura durante o processo executivo, com o objetivo de simular numéricamente a resposta não saturada do solo, usando um modelo constitutivo hipoplástico implementado para esta pesquisa e inserido em um programa de elementos finitos (Plaxis 2D) através da opção User Defined Soil Models (UDSM). Os parâmetros do modelo foram calibrados usando element tests apoiados em ensaios não saturados desenvolvidos em Charles University (Praga). O modelo computacional usado leva em conta variáveis relacionadas ao interação ambiente-solo, i.e. foram impostas cargas de chuva no modelo para observar a resposta de contenção quando muda a sucção no perfil estratigráfico. Além do caso de análise o modelo constitutivo de referência foi validado considerando outra contenção do DF com similares características.
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Condiciones técnicas para la ejecución de infraestructuras de movilidad y transporte en Bogotá

Hernán Antonio González-Urrego, Juan Carlos Ruge-Cárdenas, Carles Labraña-De Miguel.
Respuestas. Vol. 19 Núm. 1 (2014).

Colombia está en un proceso de crecimiento económico acelerado, debido al gran atractivo geopolítico con el que cuenta y su excelente potencial de explotación de recursos naturales. Sin embargo existe un déficit importante de infraestructuras para la movilidad y transporte en los ámbitos rural y urbano, que afecta directamente dichos procesos económicos, en la improductividad ocasionada por las ineficientes infraestructuras de movilidad terrestre que comunican al país. En el ámbito metropolitano, la situación llega a ser crítica como ocurre en Bogotá, ciudad para la cual se han realizado innumerables estudios en ejecución de redes de transporte masivo de pasajeros que no son técnicamente factibles debido a que desconocen toda la complejidad que implica su territorio. Este texto introductorio a otros más específicos de los mismos autores, contiene los parámetros básicos a veces pasados por alto en los estudios de factibilidad técnica, con el objetivo de ponerlos en conocimiento de todos los posibles agentes (como también de los futuros usuarios) que participan en la realización de estudios de construcción en infraestructuras para la movilidad y el transporte con énfasis en Bogotá, aunque algunos de sus contenidos también pueden servir de referente para otras ciudades. Mediante un análisis exhaustivo basado principalmente en información secundaria (fotografías aéreas, imágenes de satélite, fotografías del sitio, microzonificación sísmica, etc…) y experiencias en otras latitudes, se identificaron sitios neurálgicos de la ciudad de Bogotá con problemas de movilidad y que tuvieran un corredor ferroviario existente, para la implantación de un posible futuro Sistema Integrado de Transportes haciendo uso de diferentes tipologías de redes de conexión, a la luz de las necesidades de Bogotá y su conexión regional en el corto (5 a 8 años), mediano (5 a 10 años) y largo plazo (15 a 30 años) con una proyección de 30 años. De acuerdo a diferentes variables que controlan aspectos constructivos de la ciudad, como la complejidad geotécnica, gestión de cultura, recursos, tecnología de construcción, entre otros, se logró de manera conceptual diseñar diferentes alternativas constructivas para infraestructuras de movilidad y transporte considerando los aspectos ya mencionados. El planeamiento urbano de la ciudad respecto al mejoramiento de la movilidad y el transporte, depende principalmente de dos vertientes, el impacto en la calidad de vida de los usuarios (influenciada por la actividad social y económica) y la articulación con la propuesta de transporte modal de Bogotá.
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Results of unsaturated tests on metastable soils

J.C. Ruge, R.P. da Cunha & D. Mašín. Chapter In: Advances in Unsaturated Soils. 2013. Taylor & Francis Group.

The main objective of the current research is to analyze through the use of elemental simulations, unsaturated tests executed on soils with metaestable characteristics (Brasilia porous clay), which due to high porosity and kind of cementation, presents a structure temporally unstable when undergoing an increasing of wetting and/or variation of the stress state, resulting in the most of cases in a significant change of volume denominated collapse. The tests were done in the Geotechnical Lab from the University of Brasilia and Geological Institute from Charles University in Prague, considering char- acterization tests for the identification of the basic properties, tests for determination of the characteristic curve, consolidation, direct shear and triaxial, in both conditions saturated and unsaturated, as well as the porosimetry test, for the study of the mechanical behavior. The tests were reproduced using numerical modeling to elemental level, involving a hypo-plastic model for the unsaturated soils behavior.
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Modelación numérica de ensayos elementales de muestras de suelo cohesivo con inclusión de un núcleo de epoxi

Catalina Gómez Hoyos, Renato P. da Cunha, Analia Vazquez, Juan Carlos Ruge.
Simposio Argentino de Polímeros. SAP 2013. 28-30 (2013)

En este trabajo se simula numéricamente el comportamiento de una resina epoxi, inyectada dentro de una muestra cilíndrica cohesiva, mediante el uso de ensayos elementales (element test); con el fin de observar la evolución de los parámetros de resistencia al corte del conjunto y de la interface. La inclusión del núcleo de epoxi tiene como objetivo desarrollar aplicaciones para los polímeros en el área de refuerzo de suelos, los cuales podrían ser usados como anclajes para estabilizar taludes y excavaciones, en lugar de los anclajes metálicos. Para el desarrollo de la modelación numérica se usaron teorías constitutivas tradicionales y modernas del comportamiento del conjunto suelo/resina, incluyendo parámetros capaces de reproducir el deterioro del cementante dentro de la estructura del suelo. Este trabajo es el inicio de una investigación que pretende estudiar los efectos de la modificación de la interface suelo/polímero, la interface será modificada generando anclaje mecánico por fricción, mediante el mezclado de la resina epoxi con una arena, variando su distribución granulométrica.
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Gestores comunitarios del hábitat: una propuesta educativa desde la ingeniería civil para mejorar los problemas de habitabilidad de comunidades marginales. (Caso barrio Villa del Cerro. Bogotá, Colombia)

Juan Carlos Ruge Cárdenas & Camilo Alberto Torres Parra.
Revista Educación en Ingeniería. 2013, Vol. 8, N°. 16 pp 125-135.

Desde los espacios promovidos por la Universidad Piloto de Colombia para el fomento de la investigación y la proyección social en su comunidad académica, un grupo de estudiantes y profesores (investigadores) pertenecientes al programa académico de ingeniería civil han conformado el semillero de investigación en vivienda saludable, grupo donde se gestan ideas innovadoras para mejorar los problemas de habitabilidad de las personas en situación de marginalidad y con esto, lograr un cambio en el paradigma de la labor del ingeniero en relación al trabajo con comunidades. Es así como a partir de un proceso de educación comunitaria, se busca transferir el conocimiento del semillero a las poblaciones con falencias en su habitabilidad, proponiendo un modelo educativo activo y participativo en donde el asistente mejore sus condiciones de habitabilidad a partir de la transferencia de las tecnologías propuestas por el semillero. Por lo anterior, mediante un trabajo previo y participativo enfocado a identificar las problemáticas relacionadas a la habitabilidad en las viviendas, se han desarrollado proyectos enfocados al mejoramiento de la calidad del agua, la seguridad alimentaria y las buenas prácticas en vivienda saludable, legal y segura. Luego de comprobados los proyectos a transferir en los laboratorios de la Universidad Piloto de Colombia, se implementó una propuesta educativa para transferir dicho conocimiento a las comunidades que requieren de este tipo de iniciativas para mejorar su habitabilidad. Motivo por el cual en este trabajo se presenta un modelo educativo para transferir los proyectos desarrollados por los estudiantes a la comunidad del barrio Villa del Cerro ubicada en Bogotá, Colombia y la cual presenta problemas de habitabilidad en sus casas.
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