地下厂房洞室群动力反应时程分析

Dynamic Response Time-History Analysis of Underground Caverns

采用动力时程分析法,对杨房沟水电站地下厂房洞室群地震反应进行了三维非线性数值模拟,分析了洞周围岩的加速度、位移时程变化及应力分布特征.计算结果表明,在地震荷载作用下,洞室高边墙对加速度有一定放大效应;洞周围岩地震位移波形与输入地震波形一致,围岩各质点间的相对变形及围岩永久变形均较小;围岩应力分布较为合理,最大主应力及最小主应力幅值较小,地下洞室群在设计地震荷载作用下抗震稳定性较好.

The dynamic response of underground caverns under seismic load is analyzed using time-history analysis method and 3D nonlinear dynamic model. The time-history of acceleration, displacement and distribution of stress field are discussed. The results show that the free surfaces and high sidewall of powerhouse have amplification effect on acceleration. The wave form of earthquake displacement response of surrounding rock is consistent with that input earthquake; and the permanent displacement and relative displacement due to earthquake are small. The stress of surrounding rock is relatively well distributed under seismic loading; and surrounding rock has low maximum principal stress and minor principal stress. Underground caverns are stable under design earthquake load.