Nonlinear seismic analysis of high arch dam-foundation system with contraction joints

A 3-D dynamic contact unit model is developed to analyze the nonlinear seismic response of the dam-foundation system in high arch dam. In the model the effects of contraction joints in dam and fissures in abutment rock mass are taken into account and the system is assumed as a non-linear continuous body admitting the local fracture and large deformation. The model is applied to calculate the influence of transverse joints on stress and deformation of the arch dam in Xiaowan Project. The aseismic stability of the abutment is also analyzed. The result shows that the transverse joints may significantly affect the stress and deformation of the dam, and the potential cracking and sliding of the abutment will reduce the safety of the dam. However, the dam and abutment in Xiaowan Project is stable in the impounding period even the water level of reservoir reaches very high elevation.