Different crack sizes analyzed for surrounding rock mass around underground caverns in Jinping I hydropower station

Fracture mechanism of surrounding rock mass around underground caverns of Jinping I hydropower station is investigated by simulating growth and coalescence of cracks with the different scales. Effects of cracks and joints on fracture of surrounding rock mass are studied for the underground caverns of Jinping I hydropower station. It is assumed that growth of pre-existing cracks is parallel to the direction of maximum principal compressive stress or vertical to minimum principal tensile stress. Unstable propagation of secondary cracks leads to splitting and tensile failure of rock masses around downstream skewbacks and sidewalls of main powerhouse and main transformer chamber. Comparison is made for the numerical results and monitoring data. It is shown that numerical results are in good agreement with monitoring data.