Numerical Modelling and Analysis of Under-ground Caverns for Pumped Storage Hydropower

Summary: This study focuses on the impact of rock joints on large cavern stability in the context of underground pumped hydropower stations. Numerical modelling techniques are employed to analyze overall displacement patterns and identify weak points in the cavern design. The study compares results from models using different joint models and investigates the effects of joint orientation, stiffness, and fracture size distribution on cavern stability. Findings indicate that while certain joint models can identify weak points, they may generate unrealistic deformations. The joint dip angle is found to significantly influence cavern stability under high lateral stress, and the stiffness parameters exhibit a nonlinear relationship with displacement. The study recommends the use of more realistic Discrete Fracture Network models when accurate joint data is available. Potential improvements in cavern design are also discussed, providing guidance to engineers in the initial design stage.