高地应力和高(外、内)水压力是影响深埋引水隧洞围岩稳定性及衬砌结构安全性的主要因素。基于等效饱和多孔介质理论,将裂隙岩体和衬砌混凝土视为具有透水特性的弹塑性损伤材料,并考虑各自的变形特性与渗透系数的动态演化规律,进行锦屏二级水电站深埋引水隧洞围岩与衬砌结构施工期和运行期渗流-应力全耦合分析。分析结果表明:施工期隧洞周边排水对开挖损伤区影响较大,内水外渗现象对地下水位和围岩结构的安全性影响不大,但内水外渗情况下隧洞的开挖损伤区对衬砌结构较为不利,将导致该部位混凝土出现拉损伤区和压损伤区,应对开挖损伤区采取一定的处理措施。
High in-situ stress and high water pressure are the main factors influencing the stability of rock mass and safety of lining structures for the deep diversion tunnels. Based on equivalent saturated porous media theory and considering rock mass and concrete of lining structures as permeable media, the seepage-stress coupling analysis of diversion tunnel at Jinping II hydropower station during its excavation and operation period were carried out. The results show that the drainage around tunnel boundary has great influence on forming excavation damaged zone during construction period; seepage in the reinforced concrete lining from inner tunnel to outer tunnel has little effect on water table and rock mass stability; but this phenomenon would influence the safety of lining structures near the excavation damaged zone, so as to lead tensile and compressive damage regions in the lining structure. Corresponding countermeasures for excavation damged zones should be taken.