基于拟静力法的地下洞室群地震响应分析

以白鹤滩水电站地下厂房洞室群为研究背景,通过有限元程序Phase²建立13号机组剖面数值分析模型,基于弹塑性本构关系,采用拟静力法研究了在不同地震加速度作用下洞室群的变形及应力变化特征。结果表明:在不同地震输入方向下,洞周各关键点的位移、应力及洞室边墙相对位移变化不同,在-0.34 g的地震加速度作用下,尾调室顶拱的位移及上下游边墙的相对位移分别达到34.5 cm、12.2 cm,在0.34 g的地震加速度作用下,尾调室顶拱出现了较大的应力集中,其中最大主应力增加了12.8 MPa,会对尾调室的稳定性产生不利影响。

Seismic Response Simulation of Underground Cavern Group Based on Quasi-Static Method

The two-dimensional simulation model of underground cavern group of Baihetan Hydroelectric Station is established by the finite element software of Phase². The deformation and stress fields of underground cavern group under different seismic accelerations are simulated by the quasi-static method. The results show that the displacements, stress of key points around caverns and relative displacements of side wall of the cavern differ under different seismic input direction. Under -0.34 g accelerations, the displacement of top arch of tailrace surge chamber is 34.5cm, and the relative displacement between two walls is 12.2cm. Under 0.34g acceleration, the stress concentration occurs in top arch of tailrace surge chamber, with 12.8MPa increase in max stress, which has adverse effect on stability of tailrace surge chamber.