The deformation and stability of dam abutment have great influence on stress states of arch dam under complicated geological conditions. It is necessary to consider the interaction between arch dam and dam abutment. In order to built three- dimensional finite element model easier and describe complicated geological conditions better

arch dam finite element model and dam abutment finite element model are built respectively and the iterative calculation method is adopted to simulate the interaction between them. Based on the theory of unloading rock mass mechanics

the stress-strain state of dam abutment rock mass is studied under thrust force of arch dam after excavation unloading. The results show that the displacements of abutment slot both upstream and downstream are not remarkable. The effect of the dam thrust against the slope displacement can not be neglected.