高地应力下地下厂房围岩破坏特征及地质力学机制

摘要

结合前期地质勘查、施工期地质编录及其他施工信息,分析四川猴子岩水电站地下厂房围岩及支护结构变形开裂特征,对围岩变形破坏的地质力学机制进行研究,并对后续开挖支护提出相应的工程应对措施.研究结果表明:主厂房围岩破坏以应力驱动型为主,本质上是高地应力和低强度应力比造成的;厂区地应力及其方向使得主厂房上下游侧岩锚梁-拱肩之间边墙部位的切向应力加载效应明显,围岩易于压致劈裂;利用应力莫尔圆解释了该地区围岩易于出现破坏的原因.%Combined with the previous geological exploration,geological record during the construction and some other construction information,the cracking and deformation characteristics of the surrounding rock and supporting structure of Houziyan hydropower station were analyzed,and the geomechanics mechanism of surrounding rock deformation and failure was researched.Some corresponding engineering response measures for the subsequent excavation and support were put forward.The results show that the failure of surrounding rock in main powerhouse is mainly stress-driven,and essentially caused by high geostress and low strength stress ratio.In the sidewall between the rock anchor beam and spandrel of upstream and downstream in the main powerhouse,the tangential stress loading effect is obvious due to the stress magnitude and its direction,and the surrounding rock is easy to pressure-induced splitting.This explained why the surrounding rock mass of this area is easy to be damaged.