Construction simulation and sensitivity analysis of underground caverns in fault region

Abstract

The underground caverns of hydropower stations have a large scale and its stability depends on the complicated condition of the rock quality, the ground stress distribution, the shape and size of caverns, the excavation sequence, the support methods. To ensure the safety of the underground structures, it is necessary to study the influencing factors based on the realistic construction methods. During the exploration survey of the rock mass and geological conditions, the mechanical behaviors are usually obtained with uncertainty. Among these factors, the mechanical properties of rock and faults are important to the displacement and stress of underground caverns. In this study, the displacements and stresses during the excavation procedure of underground caverns of a hydropower station in fault region were analyzed using plastic finite element method. Subsequently, a sensitivity analysis was performed to quantitatively analyze the influence of uncertainty of the exploration survey to the safety of the underground caverns.