Influencia del grado de anisotropía de la conductividad hidráulica de los suelos en la estabilidad de taludes.
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Date
2025
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Universidad de Concepción
Abstract
Los deslizamientos de taludes son fenómenos geológicos que, a lo largo del tiempo, han provocado importantes consecuencias sociales y económicas. Entre los principales factores que los desencadenan se encuentran las precipitaciones, ya que estas modifican las propiedades del suelo al disminuir su resistencia al corte, alterar su comportamiento mecánico y erosionar su estructura interna.
Un parámetro clave en la caracterización geotécnica del suelo es la conductividad hidráulica. No obstante, gran parte de los análisis de estabilidad de taludes asumen un comportamiento isotrópico, es decir, un valor de conductividad igual en todas las direcciones, lo que simplifica el modelamiento de la disipación de presiones de poros. Esta suposición difiere de la naturaleza típicamente anisotrópica de los suelos, lo que sugiere que la anisotropía podría tener un rol decisivo en la respuesta hidráulica del talud y, en consecuencia, en su estabilidad.
En este estudio se analiza la influencia de la anisotropía en la conductividad hidráulica sobre la estabilidad de taludes, mediante la implementación de un modelo en el software GeoStudio para taludes de arena y arcilla con distintas inclinaciones y eventos de precipitación ocurridos en el país, bajo diversas razones de anisotropía (𝑘𝑥/𝑘𝑦). Lo anterior, con el propósito de identificar las condiciones en las que la anisotropía adquiere mayor relevancia y cuantificar su efecto sobre el comportamiento del talud.
De los 40 casos analizados se concluye que la anisotropía en la conductividad hidráulica no genera un cambio sustancial en la estabilidad del talud, para los suelos estudiados. En cuanto a la arcilla, la diferencia en el índice de confiabilidad es de máximo un 0.3% en el talud de 30° en el evento del 2005 entre los casos isotrópico y de mayor razón de anisotropía (𝑘𝑥/𝑘𝑦 = 10). El mayor efecto en la estabilidad al aplicar anisotropía se detectó en el caso de la arena limosa, con pendiente de 60°, al comparar 𝑘𝑥/𝑘𝑦 = 1 con 𝑘𝑥/𝑘𝑦 = 10, donde se evidenció una diferencia del 5.7% en el índice de confiabilidad al décimo día en las precipitaciones del 2000. Sin embargo, este valor no resulta determinante para justificar su consideración obligatoria en el diseño, demostrando así la razón de no considerar la anisotropía de la conductividad hidráulica de los suelos en los modelos de ingeniería geotécnica.
Slope landslides are geological phenomena that, over time, have caused significant social and economic consequences. Among the main triggering factors are precipitation events, as they modify the properties of the soil by decreasing its shear strength, altering its mechanical behavior, and eroding its internal structure. A key parameter in the geotechnical characterization of soil is hydraulic conductivity. However, most slope stability analyses assume isotropic behavior, that is, a conductivity value that is equal in all directions, which simplifies the modeling of pore pressure dissipation. This assumption differs from the typically anisotropic nature of soils, suggesting that anisotropy could play a decisive role in the hydraulic response of the slope and, consequently, in its stability. This study analyzes the influence of anisotropy in hydraulic conductivity on slope stability through the implementation of a model in the GeoStudio software for sandy and clayey slopes with different inclinations and precipitation events that occurred in the country, under various anisotropy ratios (𝑘𝑥/𝑘𝑦). The objective is to identify the conditions under which anisotropy becomes more relevant and to quantify its effect on slope behavior. From the 40 cases analyzed, it is concluded that anisotropy in hydraulic conductivity does not cause a substantial change in slope stability for the soils studied. In the case of clay, the difference in the reliability index is at most 0.3% in the 30° slope during the 2005 event between the isotropic case and the one with the highest anisotropy ratio (𝑘𝑥/𝑘𝑦 = 10). The greatest effect on stability due to anisotropy was detected in the silty sand case, with a 60° slope, when comparing 𝑘𝑥/𝑘𝑦 = 1 with 𝑘𝑥/𝑘𝑦 = 10, where a 5.7% difference in the reliability index was observed on the tenth day during the 2000 precipitation event. However, this value is not decisive enough to justify its mandatory consideration in design, thereby demonstrating the rationale behind not considering soil hydraulic conductivity anisotropy in geotechnical engineering models.
Slope landslides are geological phenomena that, over time, have caused significant social and economic consequences. Among the main triggering factors are precipitation events, as they modify the properties of the soil by decreasing its shear strength, altering its mechanical behavior, and eroding its internal structure. A key parameter in the geotechnical characterization of soil is hydraulic conductivity. However, most slope stability analyses assume isotropic behavior, that is, a conductivity value that is equal in all directions, which simplifies the modeling of pore pressure dissipation. This assumption differs from the typically anisotropic nature of soils, suggesting that anisotropy could play a decisive role in the hydraulic response of the slope and, consequently, in its stability. This study analyzes the influence of anisotropy in hydraulic conductivity on slope stability through the implementation of a model in the GeoStudio software for sandy and clayey slopes with different inclinations and precipitation events that occurred in the country, under various anisotropy ratios (𝑘𝑥/𝑘𝑦). The objective is to identify the conditions under which anisotropy becomes more relevant and to quantify its effect on slope behavior. From the 40 cases analyzed, it is concluded that anisotropy in hydraulic conductivity does not cause a substantial change in slope stability for the soils studied. In the case of clay, the difference in the reliability index is at most 0.3% in the 30° slope during the 2005 event between the isotropic case and the one with the highest anisotropy ratio (𝑘𝑥/𝑘𝑦 = 10). The greatest effect on stability due to anisotropy was detected in the silty sand case, with a 60° slope, when comparing 𝑘𝑥/𝑘𝑦 = 1 with 𝑘𝑥/𝑘𝑦 = 10, where a 5.7% difference in the reliability index was observed on the tenth day during the 2000 precipitation event. However, this value is not decisive enough to justify its mandatory consideration in design, thereby demonstrating the rationale behind not considering soil hydraulic conductivity anisotropy in geotechnical engineering models.
Description
Tesis presentada para optar al título de Ingeniero/a Civil.
Keywords
Anisotropía, Taludes (Geología), Propiedades del suelo, Mediciones hidráulicas