关键词: 岩石力学, 防渗层, 排水, 三维渗流计算, 地下厂房, 锦屏二级水电站

Abstract: Jinping II Hydropower Station, located in Liangshan Autonomous Prefecture of Sichuan Province, is a highest water head and biggest capacity one at the in Yalong River. The underground powerhouse, the core of the project, is situated in right bank of V-shaped valley of the Yalong River. It meets the complicated groundwater seepage environment. For the safety of underground caverns, a reasonable layout of impermeable layer and discharge outlet is put forward based on the new design principle which is ponding first and discharge second, free drainage of high head wall, pumping of low head water, separating out water and inner water. Based on the result of 3D seepage numerical calculation of powerhouse region, the parameters of layer and discharge outlet system are also decided, which considers a rational safety scope. Practice of excavation of caverns proves that the design of seepage control and drainage system is reliable.

Key words: rock mechanics, impermeable layer, discharge outlet, 3D seepage numerical calculation, large underground powerhouse, Jinping II Hydropower station