一、前言圈岩稳定是水电站地下洞室设计和施工中的一个重要问题。影响洞室围岩稳定的因素很多,如初始地应力场、围岩强度、软弱结构面、洞室体型、洞室尺寸、洞室群相互作用、施工开挖过程及支护情况等。其中,软弱结构面是 I. Introduction Rock stability is an important issue in the design and construction of underground caverns of hydropower stations. There are many factors that affect the stability of surrounding rock in the cavern, such as initial stress field, surrounding rock strength, weak structural plane, cavern size, cavern size, cavern group interaction, excavation process and support conditions. Among them, the weak structure is