The seismic wave input method for soil-structure dynamic interaction analysis based on the substructure of artificial boundaries

：Numerical simulation is an important approach to conduct soil-structure dynamic interaction analysis, while the realization of the seismic wave input determines the accuracy of the simulation. Wave method is one of the most commonly used methods for seismic wave input, which converts the input wave into the equivalent loads on the artificial boundaries. Comparing with other methods, the wave method has high precision, but the implementation is relatively complicated. Based on another form of equivalent input seismic loads in the finite element model, a new seismic wave input method was proposed. In the new method, by imposing the free-field displacements on the nodes of the substructure composed of the elements containing the artificial boundary nodes, the equivalent input seismic loads are obtained through dynamic analysis of the substructure. Afterwards, the equivalent input seismic loads are applied to the nodes of the artificial boundaries to complete the seismic wave input and the seismic analysis of the soil-structure dynamic interaction model are performed. In comparison with the original wave method, the new method avoids the complex processes of calculating the free field stress on the artificial boundaries and the additional forces caused by the artificial boundaries, and determining the directions of the loads on different artificial boundaries. Therefore, it is simple to calculate the equivalent input seismic loads and easy to implement the seismic wave input process in the new method. The validity of the new method is verified by the numerical examples of the seismic analysis of the elastic half-space and layered half-space under vertical and oblique incident seismic waves.