Desempeño sísmico de pilotes geotérmicos.
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Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad de Concepción
Abstract
Dada la necesidad presente de generar fuentes de energía sustentables, el uso de la energía geotérmica y las aplicaciones en el campo de la ingeniería civil se ha propuesto el uso de los Pilotes Geotérmicos, los cuales cumplen una función dual como intercambiadores de calor y cómo elementos de fundación. Durante su operación, los pilotes geotérmicos son sometidos a cambios de temperatura, los que inducen deformaciones y esfuerzos en el material circundante. La respuesta de la interfaz suelo-pilote, alterada por los cambios térmicos y sometida a cargas sísmicas, no es clara. Este estudio evalúa la respuesta sísmica de los pilotes geotérmicos, analizando desde una perspectiva multidisciplinaria los efectos de los ciclos térmicos sobre el suelo y el eventual cambio en su comportamiento mecánico y dinámico. Empleando PLAXIS 2D, se utiliza el método de elementos finitos para modelar un pilote geotérmico aislado sometido a variaciones de temperatura, carga estática y carga sísmica. Los ciclos térmicos producen una redistribución de los esfuerzos y variaciones en la resistencia de fuste en régimen estático. Se estudió la respuesta sísmica del pilote analizando el efecto de los ciclos térmicos en los asentamientos sísmicos obtenidos. Dichos asentamientos fueron fuertemente influenciados por el contenido de energía del movimiento incidente, el que se caracterizó por medio de la Duración Significativa (D05-95) y la Velocidad Absoluta Acumulada (CAV). Se obtuvo un grado elevado de correlación entre el CAV y los asentamientos sísmicos. Se encontraron diferencias entre un 3% y un 5% en los asentamientos sísmicos obtenidos para un mismo registro sísmico y distintos ciclos térmicos. Similarmente, se obtuvieron diferencias del 1% en la tensión admisible. El estudio realizado arroja luces sobre la aplicabilidad de los pilotes geotérmicos en ambientes activos sísmicamente.
Given the need to change energy sources towards more sustainable systems, the use of geothermal energy and its application in the field of civil engineering has introduced the use of energy piles. During their operation, energy piles are subjected to temperature variations, which induce deformations and stress in the surrounding geomaterial. When this altered interface is subjected to earthquake loading, the system response is unclear. This study evaluates the seismic performance of energy piles, analyzing from a multidisciplinary perspective the effect of thermal cycles on soils and their eventual change in mechanical and seismic behavior. Using PLAXIS 2D, a finite element analysis of an energy pile subjected to temperature variations, static, and seismic loads was carried out. The thermal cycles produced a redistribution of stress and variations in their shaft resistance under a static scenario. We studied the seismic performance of the pile by analyzing the effect of the thermal cycles on the calculated seismic-induced settlements. These settlements were strongly influenced by the energy content of the incident motion, which was characterized by Significant Duration (D05-95) and Cumulative Absolute Velocity (CAV). From these intensity measures, CAV showed the strongest correlation with the observed seismic settlements. We found differences between 3% and 5% in the seismic settlements, when comparing models with different thermal cycles and the same seismic input. Furthermore, differences of 1% were obtained for the allowable pressure. Our investigation shades light into the suitability of energy piles in seismic environments.
Given the need to change energy sources towards more sustainable systems, the use of geothermal energy and its application in the field of civil engineering has introduced the use of energy piles. During their operation, energy piles are subjected to temperature variations, which induce deformations and stress in the surrounding geomaterial. When this altered interface is subjected to earthquake loading, the system response is unclear. This study evaluates the seismic performance of energy piles, analyzing from a multidisciplinary perspective the effect of thermal cycles on soils and their eventual change in mechanical and seismic behavior. Using PLAXIS 2D, a finite element analysis of an energy pile subjected to temperature variations, static, and seismic loads was carried out. The thermal cycles produced a redistribution of stress and variations in their shaft resistance under a static scenario. We studied the seismic performance of the pile by analyzing the effect of the thermal cycles on the calculated seismic-induced settlements. These settlements were strongly influenced by the energy content of the incident motion, which was characterized by Significant Duration (D05-95) and Cumulative Absolute Velocity (CAV). From these intensity measures, CAV showed the strongest correlation with the observed seismic settlements. We found differences between 3% and 5% in the seismic settlements, when comparing models with different thermal cycles and the same seismic input. Furthermore, differences of 1% were obtained for the allowable pressure. Our investigation shades light into the suitability of energy piles in seismic environments.
Description
Tesis presentada para optar al Magister en Ciencias de la Ingeniería con mención en Ingeniería Civil
Keywords
Pilotes (Ingeniería civil), Recursos geotérmicos, Dinámica estructural