Global stability coefficient of large underground caverns under static loading and earthquake wave condition

Underground energy and resource development, deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances. An evaluation method of the global stability coefficient of underground caverns based on static overload and dynamic overload was proposed. Firstly, the global failure criterion for caverns was defined based on its band connection of plastic-strain between multi-caverns. Then, overloading calculation of the boundary geostress and seismic intensity on the caverns model was carried out, and the critical unstable state of multi-caverns can be identified, if the plastic-strain band appeared between caverns during these overloading processes. Thus, the global stability coefficient for the multi-caverns under static loading and earthquake was obtained based on the corresponding overloading coefficient. Practical analysis for the Yingliangbao (YLB) hydraulic caverns indicated that this method can not only effectively obtain the global stability coefficient of caverns under static and dynamic earthquake conditions, but also identify the caverns' high-risk zone of local instability through localized plastic strain of surrounding rock. This study can provide some reference for the layout design and seismic optimization of underground cavern group.