Abstract: Underground caverns of Jiangping River Hydropower Station arranged for the diversion tunnel, flood discharge tunnel, spillway No.1, spillway No.2 in turn, caverns of which are intensive, geological conditions are complex and constructions are difficult. The authors simulate caverns mainly in three-dimensional model; while simulate the three chambers slopes of the outlet, four large faults , the actual shape of a number of rock stratification and slope table accuratly. Prestressed anchor cable, anchor bolt and lining systems and other support measures are used in the project after excavation. The prestressed anchor bolt is simulated accuratly in supporting calculations. System of anchor bolts are simulated by using two-dimensional submodel for equivalent calculations. These measures ensure the necessary accuracy, but also improve the modeling and calculation efficiency. For the secondary lining simulation, the shell unit of three-dimensional shell structure is used to get revised deformation parameters of the initial lining and secondary lining considering the effect of anchor bolt lining through two displacement equivalent. Lining thickness has been optimized according to the deformation trends of the key points and the greatest moment change of cavern. Cavern bending moment and shear force value can be read though lining unit effectively. Bending and shear force values of lining structural of the most dangerous condition provide a reference for the reinforcement. The diagram of displacement values and the plastic zone map before and after the reinforcement are given in the calculation results. And the reinforcement measures significantly reduce the maximum displacements and the plastic zone.

Key words: underground caverns, FLAC3D, anchor cable, lining, anchor bolt, stability