江口水电站地下厂房围岩稳定性研究

Research on the Surrounding Rock Stability of Jiangkou Hydroelectric Power Station Underground Workshop

重庆市芙蓉江江口水电站采用引水式地下厂房,是由许多建筑物组成复杂的地下空间结构,主厂房布置于左岸山体内,因此地下洞室稳定是整修工程建设的关键技术问题之一。电站地下洞室围岩以厚层灰岩、白云岩为主,夹少量页岩。洞室地应力以构造应力为主,其最大主应力方向与厂房轴线方向近垂直。根据地应力及山体地形地质条件,采用三雏弹塑性有限元分析方法进行分析,拟合回归出计算模型所需的三维初始应力场,并模拟开挖及支护方案,计算得出洞室周边塑性变形区、应力分布及位移。并进行了稳定分析,采用支护措施后地下洞室塑性变形开裂范围和位移及洞周应力均有减少,使室洞围岩稳定是有保证的。

Chongqing Jiangkou hydroelectric power station＇s underground power house contains numerous complicated underground structures, the power house constructed in the mountain, so the stability of underground cave is the key technical problem. The surrounding rock of the cave consists of thick - layer limestone, dolomite and a little shale. The cave＇s initial principal stress is tectonic stress, and the max main stress＇s direction is perpendicular to the power house＇s stalk line. According to the stress and geological conditions, using three-dimensional elastoplastic nu- merical simulation, the authors fit three-dimensional initial stress field for simulation model, imitate excavating and support project, compute cave＇s plastic district, stress field and displacement. The result of stability analysis is that, when the fitting support measures adopted, the plastic district, stress and displacement of cave＇s surrounding rock mass is less, the surrounding rock mass is stable.