地震力作用下软基土石坝的动力响应分析

Dynamical response analysis of the earth-rock dam on soft soil during earthquake

采用二维动力有限元方法并结合有效应力法对栖凤湖土石坝受地震作用的动力响应进行了分析。分析时上游采用校核洪水位198.5 m,下游为180 m。地震峰值加速度为0.275g,持续时间为10 s。计算结果表明,震后孔隙水压力与震前相比,增加了将近1倍,在粘土心墙和淤泥土地基中出现了孔隙水压力等于侧向固结压力区域,这对土石坝的稳定极为不利。通过对坝体表面各点的动力反应分析,发现位于坝体表面中部D和E点的位移和加速度峰值均比其他部分的大。

Two dimensional dynamical finite element and effective stress method were used to analyze dynamical response of Qifenghu Lake earth - rock dam during earthquake. During analysis, the floodwater level in the upriver was 198.5 m and 180 m in the downriver. Peak acceleration of earthquake was 0. 275 g and it lasted 10 s. Calculation results show that pore water pressure after earthquake is as near twice as that before earthquake. Some region in the central clay wall and the silt groundsill where pore water pressure is equal to literal consolidation pressure was found. This will endanger the stability of the dam. Through analyzing dynamical response of nodes on the dam surface, absolute peak acceleration and peak displacement of D and E node in the middle of the dam is greater than those of others.