平原水库土石坝饱和砂土地基地震液化分析

Seismic Liquefaction Analysis of Saturated Sandy Soil Foundation of Plain Reservoir

本文运用FLAC3D有限差分软件对某水库大坝地基可液化土层在不同库水位作用下的液化特性进行动力反应分析,探讨了饱和砂土地基在地震作用下的孔隙水压力变化过程以及土石坝各典型节点的加速度和位移响应.结果表明:在设防烈度为Ⅶ度的情况下,距离坝体较远的可液化土层易发生液化,库水位处于高水位时上游坝脚附近的可液化土体发生液化的可能性较低水位时小,但下游坝脚处可液化土层发生液化的可能性较低水位高,坝体下方可液化土体最难液化.坝顶的加速度峰值放大倍数最大,坝基液化土体过滤了地震波的高频成分,减缓了地面节点的加速度.坝体周围出现了不同程度的隆起现象,坝体整体的水平位移大于竖向位移.

FLAC3 Dis used to analyze the characteristics of liquefaction of saturated sandy soil foundation in a reservoir dam foundation with liquefaction soil under different water levels.How the pore water pressure changes under seismic loading is discussed and the displacement responses of earth-rock dam in various typical nodes are analyzed.The results show that under the condition of the fortification intensity of seven degrees,the liquefaction soil approaching the toe of the dam in a low upstream water level is more likely to liquefy than it is in a high water level;but the liquefaction soil approaching the foot of the dam in a low water level is less likely to liquefy than it is in a high water level.The liquefaction soil beneath the body of the dam is the most difficult to liquefy.The horizontal displacement of the dam body is greater than that of vertical displacement.