Sistema revisado de clasificación de suelos (SRCS) como herramienta para la susceptibilidad a la licuación.
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Date
2026
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
La susceptibilidad a la licuación en mezclas arena–finos constituye una preocupación central en ingeniería geotécnica, debido a la dificultad que presentan los suelos transicionales para ser representados mediante criterios convencionales, basados en el contenido de finos e índice de plasticidad. La práctica actual emplea estos parámetros para orientar la evaluación preliminar del comportamiento del suelo frente a carga cíclica, sin embargo, su capacidad de discriminación resulta limitada cuando la fracción fina comienza a modificar la matriz resistente sin alcanzar aún los umbrales fijos comúnmente adoptados. En este estudio, se evalúa la capacidad del Sistema Revisado de Clasificación de Suelos (SRCS), para organizar e interpretar el comportamiento cíclico de mezclas arena–finos, a partir de ensayos triaxiales cíclicos no drenados.
Se desarrolló un programa experimental sobre mezclas reconstituidas elaboradas con arena Biobío y tres tipos de finos de distinta naturaleza, considerando variaciones en el contenido de finos y en la relación de vacíos inicial, junto con la caracterización de los materiales mediante la determinación de sus propiedades físicas e índice. Se ejecutaron ensayos triaxiales cíclicos no drenados bajo condiciones controladas de saturación, consolidación y carga, y la respuesta se examinó a partir de la acumulación de deformación, la generación de presión de poros, las trayectorias de esfuerzos efectivos y los mecanismos de inestabilidad desarrollados. El análisis confirma que la respuesta cíclica depende de la interacción entre el estado inicial, el tipo y el contenido de finos, y que la mayor variabilidad del comportamiento se concentra en la zona transicional.
Finalmente, se establece que la influencia de los finos sobre la respuesta cíclica comienza a manifestarse para contenidos inferiores al 20% y que la sensitividad eléctrica (𝑆𝐸) presenta una capacidad de discriminación superior a la del índice de plasticidad para organizar la respuesta observada. Asimismo, se confirma que el SRCS permite representar de manera más consistente comportamientos transicionales, que no son adecuadamente capturados por criterios actuales. Esto respalda el uso de clasificaciones con mayor fundamento físico para interpretar la susceptibilidad a la licuación en mezclas arena–finos y para apoyar una selección más fundamentada de los procedimientos de análisis aplicables al estudio del comportamiento sísmico del terreno.
Liquefaction susceptibility in sand–fines mixtures constitute a central concern in geotechnical engineering, due to the difficulty of representing transitional soils through conventional criteria, based on the fines content and plasticity index. Current practice uses these parameters to guide the preliminary assessment of soil behavior under cyclic loading, however, their discriminatory capacity becomes limited when the fine fraction begins to modify the load-bearing matrix without yet reaching the commonly adopted fixed thresholds. In this study, the capacity of the Revised Soil Classification System (RSCS) to organize and interpret the cyclic behavior of sand–fines mixtures is evaluated, based on undrained cyclic triaxial tests. An experimental program was developed on reconstituted mixtures prepared with Biobío sand and three types of fines of different nature, considering variations in fines content and initial void ratio, together with the characterization of the materials through the determination of their physical and index properties. Undrained cyclic triaxial tests were performed under controlled saturation, consolidation, and loading conditions, and the response was examined based on strain accumulation, pore-pressure generation, effective stress paths, and the instability mechanisms developed. The analysis confirms that the cyclic response depends on the interaction among the initial state, the type and content of fines, and that the greatest variability in behavior is concentrated in the transitional zone. Finally, it is established that the influence of fines on cyclic response begins to manifest for contents below 20% and that electrical sensitivity (𝑆𝐸) presents a greater discriminatory capacity than the plasticity index for organizing the observed response. Likewise, it is confirmed that the RSCS allows transitional behaviors to be represented more consistently, which are not adequately captured by current criteria. This supports the use of classifications with a stronger physical basis to interpret liquefaction susceptibility in sand–fines mixtures and to support a more informed selection of analysis procedures applicable to the study of the seismic behavior of the ground.
Liquefaction susceptibility in sand–fines mixtures constitute a central concern in geotechnical engineering, due to the difficulty of representing transitional soils through conventional criteria, based on the fines content and plasticity index. Current practice uses these parameters to guide the preliminary assessment of soil behavior under cyclic loading, however, their discriminatory capacity becomes limited when the fine fraction begins to modify the load-bearing matrix without yet reaching the commonly adopted fixed thresholds. In this study, the capacity of the Revised Soil Classification System (RSCS) to organize and interpret the cyclic behavior of sand–fines mixtures is evaluated, based on undrained cyclic triaxial tests. An experimental program was developed on reconstituted mixtures prepared with Biobío sand and three types of fines of different nature, considering variations in fines content and initial void ratio, together with the characterization of the materials through the determination of their physical and index properties. Undrained cyclic triaxial tests were performed under controlled saturation, consolidation, and loading conditions, and the response was examined based on strain accumulation, pore-pressure generation, effective stress paths, and the instability mechanisms developed. The analysis confirms that the cyclic response depends on the interaction among the initial state, the type and content of fines, and that the greatest variability in behavior is concentrated in the transitional zone. Finally, it is established that the influence of fines on cyclic response begins to manifest for contents below 20% and that electrical sensitivity (𝑆𝐸) presents a greater discriminatory capacity than the plasticity index for organizing the observed response. Likewise, it is confirmed that the RSCS allows transitional behaviors to be represented more consistently, which are not adequately captured by current criteria. This supports the use of classifications with a stronger physical basis to interpret liquefaction susceptibility in sand–fines mixtures and to support a more informed selection of analysis procedures applicable to the study of the seismic behavior of the ground.
Description
Tesis presentada para optar al título de Ingeniero/a Civil.
Keywords
Licuación, Ingeniería geotécnica, Suelos Clasificación