The exponential nonlinear dynamic contact models

combined with point-to-surface contact mo-dels

are adopted for analyzing dynamic response of arch dam with key slots.Due to the complexity of the real structure of key slots

it needs to be simplified for the purpose of the research.Compared with the results of the flat joint models

the detailed studies of the key slot models concerns about the change law of the normal joint opening

the radial sliding and its effect on the dam stress states are carried out.A planning concrete arch dam as an instance is presented in the paper to discuss the effect of the contraction joint and induced joint on the work behavior of the dam.Additionally

the comprehensive analysis on the effect of key slot is also provided.The results show the radial slid of the arch dam with flat joints comparing to the normal opening is dominating

and the opening of contraction joints will increase with the induced joint which may weaken the stiffness and the integrity of the dam

but the induced joint have a less effect on the dam stress.Comparing with the flat joint models

the radial sliding of the key slot models will greatly decrease while the normal opening will increase;the maximum principal tension stress of the dam heel and the maximum arch stress of the crown cantilever crest will also increase.