Stability Analysis of Slope and Diversion Water Tunnel of Hydropower Station under Strong Earthquake

Abstract

According to the slippage of the slope under the action of strong earthquakes and the deformation of the lining structure of the diversion water tunnel, the hydropower station under the seismic load with a 100-year probability of exceeding 2% was simulated, and the three-dimensional dynamic finite element method was used to analyze the slope of the powerhouse and the diversion water tunnel, and obtained the stress and displacement laws of the slope and the water diversion tunnel lining structure and the dynamic response characteristics of the tunnel. The results showed that under the influence of ground motions, the slope and the lining structure of the diversion water tunnel would produce similar forced vibrations, and the damage effect at the top of the slope was more obvious than that at the empty face. The dynamic displacement, tensile stress and compressive stress increased with the increase of the peak ground motion. The maximum values of tensile and compressive stress of the tunnel lining structure appeared at the entrance of the upper flat section of the diversion water tunnel, and there would be local tensile stress concentrations at the top, bottom and the middle of the tunnel. Due to the existence of adjacent tunnels, the tensile stress generated by the tunnel lining was asymmetric in the horizontal direction, and the mutual influence between the two tunnels increased the maximum tensile stress accordingly.