Seismic Response Analyses of a Large-Span Powerhouse Cavern Considering Rock–Structure Interaction

Underground structures in earthquake-prone zones should be designed to withstand both static overburden pressures and earthquake shocks. This paper presents a case study on a large-span powerhouse cavern. With seismic data selected from past earthquake records, lab and in situ tests of the cavern’s geological and geomechanical conditions were performed to analyze the static and dynamic stability of the cavern through the continuum modeling approach. Performance analyses via both 2D and 3D modeling were carried out under seismic conditions and for selected design ground motions. The dynamic response of the surrounding rock mass and of the reinforcement system was detected. The results obtained will facilitate future stability analyses of large underground caverns constructed in the past on the basis of seismic design analyses and input data from post-earthquake records that were recently made available on the site.