地震与强降雨条件下云南鲁甸王家坡震裂山体稳定性分析

Analysis on the stability of seismic-slope in Wangjiapo under earthquake and strong raining

强震、暴雨等极端工况下的动力响应研究是震裂山体稳定性分析的关键。针对云南省鲁甸县红石岩堰塞坝水电库区边坡稳定性问题,运用三维数值模拟手段,对王家坡震裂山体在竖向和水平向地震波耦合作用下的动力响应全过程进行研究,并与暴雨工况及天然工况进行对比。研究结果表明:强震及暴雨作用下,王家坡震裂山体主要位移变形均发生在山体上部的断层影响带全强风化层表层部位,最大位移量分别为0.64 m和0.28 m;结合应力分布及剪应变增量分析可知,斜坡整体最大变形方向为N7°W。在天然状态下,坡体整体稳定性较好,但在极端工况下,坡体上部全强风化层发生坡表局部失稳的可能性较大。动力稳定性分析结果与实际监测数据较吻合,可为红石岩水电库区建设及王家坡震裂山体边坡治理提供参考依据。

The dynamic response under earthquake and strong raining loading were the critical factor of seismic-slope dynamic stability researches. Three dimensional numerical simulation has been used,coupled with the vertical and horizontal seismic wave,to analyze the whole process of dynamic response of Wangjipo seismic slope stability at Hongshiyan hydropower station in Ludian County,Yunnan Province,China. When compared the results of earthquake loading with the results of strong raining loading and natural gravity loading,it has been shown that under the earthquake loading and strong raining loading, the main displacement deformation of the Wangjiapo seismic slope were both occurred at the completely-intensely weathered limestone layer which was on the top of the slope,and the maximum displacements were shown as0. 64 m and 0. 28 m,respectively. Through analysis of the displacements,the stress distributions and the shear strain increments,the seismic slope maximum deformation direction was N7° W. In conclusion,the stability of the whole seismic slope was well under the natural gravity loading; however,under the extreme conditions,there was a high possibility that the surface layer of the completely-intensely weathered limestone layer would be failed. The results of dynamic stability analysis proposed in this paper fitted perfectly with the actual monitoring data,could provide theoretical basis for prevention design of the Hongshiyan hydropower station and the Wangjiapo seismic slope.