深埋水电站洞室群围岩受力特性研究

结合锦屏二级水电站超深埋四孔引水隧洞工程，研究不同支护时机下洞周关键点位移、不同路径力学响应、能量密度分布规律。结果表明:典型断面隧道在毛洞状态不能稳定，最大水平位移发生在外侧隧道，且两侧极不对称，而中间隧道两侧位移基本对称；当应力释放80%时对应毛洞必须支护；拱顶深部围岩(2～3m)出现最大主应力、最大剪应力、能量密度增高带，外侧隧道拱顶深部围岩(2～3m)力学状态对洞室群稳定性起着关键作用。

Study on Surrounding Rock Mechanical Property in Caverns of Deeply-buried Hydropower Station

Combined with the ultra-deeply buried four-hole diversion tunnel of Jinping Secondary Hydropower Station,the displacement of key points in tunnel perimeter,mechanical response of different routes,energy density distribution under different supporting times are separately studied.The results show that tunnels with typical section cannot be stable in unsupported excavation;the maximum horizontal displacement occurs at the outer tunnel and is very asymmetric on both sides,while the displacement of middle tunnel is basically symmetric on both sides;when stress released 80 %,the corresponding unlined cavern must be supported;when the roof deep rock（2~3 m） appears the maximum primary stress,maximum shear stress and energy density increase,the mechanical property of the outer roof deep rock（2~3 m） plays a key role for the stability of caverns.