For the problem whether inner water has an impact on the hydrodynamic characteristics of circular hollow pier with holes

a numerical analysis model for pier-water coupling by ANSYSCFX was established.The dynamic characteristics and the dynamic response of the hollow pier with inner water under earthquake loading were studied.The results show that the inner water has great influence on dynamic characteristics.When the inner water depth is half the height of the hollow pier

the natural frequency of hollow pier is 25.08% lower than that of the only outer water

and the natural frequency is reduced by 39.32% with full water.As a result of pier vibration induced by earthquake

the inner water sloshing will increase the additional hydrodynamic force of the hollow pier

thus increasing the dynamic response of the structure（the increase rate of principal stress is 30.84%）.The interaction between inner and outer water causes the local stress near the holes to increase by 9%.The benefit of inner water resistance to outer water pressure of the hollow pier is etched away.In terms of the seismic action effect

it is not suitable for opening holes on the wall of hollow piers in deep water.