Stability Analysis of Semi-underground Caverns and Slopes for Jinshuitan Pumped Storage Power Station

With the development of renewable energy, underground pump storage power stations (PSPS) have been largely constructed in recent years, while it is important to initially analyze the stability of underground buildings. In this paper, a case study regarding semi-underground caverns and slopes stability of Jinshuitan PSPS has been studied with FLAC3D. Firstly, the initial stress condition of the model is validated through a two-dimensional hydraulic fracturing stress test, which displayed the maximum principal stress as 3.2 ~ 10.8 MPa with the direction of N82°W. Secondly, slope stability analysis shows that the factor of safety for slopes is larger than 3. Then, the excavation response of un-supported caverns has been simulated, which indicates that the general deformation of caverns is 24 ~ 46 mm. The plastic area depth is 4 ~ 10 m and the maximum principal stress is 10 ~ 20 MPa. Finally, initial support design has been evaluated. The deformation has generally reduced by 0 ~ 3%. Also, the plastic volume of the surrounding rock decreased by 5% ~ 12%. The stress of the anchors on the side walls in the powerhouse within 150 MPa is more than 90%. Therefore, the stability of semi-underground caverns and slopes is generally good and the support design basically meets the requirements.