如美水电站高陡边坡开挖动态卸荷响应分析

Dynamic excavation unloading response of high steep rocky slope of Rumei Hydropower Station

为避免西藏如美水电站消力池高陡边坡在施工过程中出现不稳定块体和崩塌事故,通过对坝址区地质资料的详细分析,建立了消力池高陡边坡三维有限元计算模型,并结合卸荷岩体力学理论,运用弹塑性有限元法,研究了消力池高陡边坡在开挖过程中的动态卸荷响应。综合考虑了不卸荷、一次开挖卸荷、动态卸荷工况,得到了边坡施工期的变形、应力、塑性区分布状况。计算结果表明,卸荷的影响主要体现在变形上;卸荷比不卸荷条件下的变形值、塑性区要大,且动态卸荷下的变形值比一次开挖卸荷条件下的变形值要大。

Aiming at the rocky slope excavation at stilling basin of Rumei Hydropower Station in Tibet, we established a 3D FEM model after an elaborate analysis on the geological data at the dam site. According to the theory of unloading rock mechan- ics, the dynamic unloading response of high steep rocky slope at stilling basin to excavation was investigated by elastic - plastic FEM method. The deformation, stress and plastic distribution area of the slope during construction period was obtained consider- ing 3 cases, namely non - unloading, one - time unloading and dynamic unloading. The results show that the unloading effect mainly influences deformation of slope ; the deformation value and plastic area in unloading case are larger than that in non - un- loading case, and the deformation values in dynamic unloading case is larger than that in one - time unloading case.