Hydrodynamic pressure will be produced from interaction and intercoupling between dam and reservoir during earthquake.Arch dam will subjected to impact action from hydrodynamic pressure.Air isolation technique has been applied to decrease hydrodynamic pressure and to improve shock resistant capability of arch dam. Based on the theory of fluid solid interaction, tridimensional FEM model of dam air water is introduced. Research of seismic isolation mechanism on air cushion has been formulated.Tridimensional dynamic FEM simulation for gravity dam and arch dam was accomplished respectively.It is demonstrated that air isolation obviously influences hydrodynamic pressure and acceleration response.The hydrodynamic pressure is reduced for 65% with air cushion isolation. In addition,more model tests are needed to be verify air isolation mechanism.
