The assessment method of post-earthquake reinforcement measures and calculation method of safety factor for general stability of underground caverns under earthquake effect were proposed. Firstly, the approach of simultaneous anti-shear and anti-tensile strength reduction was adopted to calculate the safety factor for general stability of underground caverns. The general stability of caverns could be easily quantitatively assessed. Afterwards, the wave filed method was employed to simulate the impacts of Wenchuan earthquake. The post-earthquake reinforcement measures taken at Yingxiuwan hydropower plant, which was located in the epicenter region, were assessed. The pre-earthquake and post-earthquake as well as pre-reinforcement and post-earthquake safety factors of underground caverns were summarized. The variation laws of safety factors indicated that the proposed methods were able to reflect earthquake influences and prove the necessity of reinforcement measures. Meanwhile, by comparing the safety factors under different calculation schemes, it was discover that the anti-seismic capacity of underground caverns could not be fully restored to the level before the earthquake. However, the reinforcement measures were able to meet the seismic fortification standard required by design codes. It was therefore concluded that the long-term stability of underground caverns can be guaranteed and the post-earthquake reinforcement measures were reliable as well. The proposed methods provided useful references to the post-earthquake restoration and reinforcement design of similar projects.
