Abstract: Since there exist some geological defects such as extensional fractures, weak layers and clay interactions in the right dam abutment of Wugachong Arch Dam, the dam abutment anti-sliding stability cannot meet the safety requirements, thus some reinforcement measures need to be taken. According to the Wugachong Arch Dam’s latest geologic data and the arch dam structure design results, a 3D numerical model for the whole arch dam is built. The joint elements for Mohr-Coulomb yield criterion are adopted to simulate the structure of the foundation’s extensional fractures, weak layers and clay interactions. Using the nonlinear finite element method, the deformation and yield region of foundation rock and structural surfaces before and after reinforcement are compared; the effectiveness of the reinforcement measures to the right bank abutment is evaluated. The deformation and yield condition’s development of arch dam and foundation rock is analyzed by using water density overload method. And the global safety of arch dam-foundation system after reinforcement is given. By comparison with similar engineering, the Wugachong Arch Dam’s global safety is evaluated comprehensively. The results show that the reinforcement measures to the extensional fracture L1can improve on the right bank abutment stability obviously. After reinforcement, Wugachong Arch Dam’s abutment has high overload safety which is superior among the high dams.

Key words: arch dam, dam abutment, shear strength reduction method, overload method, deformation, safety