Research And Application Of The Seismic Wave Input Method For Soil-Structure Dynamic Interaction Analysis

Numerical simulation is an important method to solve the problems of soil-structure dynamic interaction,and the effective seismic wave input is a key step to ensure the simulation accuracy of the seismic analysis of soi-structure dynamic interaction.This dissertation systematically studies the seismic wave input methods for soil-structure dynamic interaction analysis and the applications.The seismic wave input method based on the substructure of artificial boundaries and the seismic wave input method based on the internal substructure are proposed.Based on the new methods,the applications are studied,including that the multi-scale analysis method for seismic analysis of the structures in near-source complicated sites and the mixed wave field technique for seismic wave input are proposed.Finally,based on the proposed methods,the dynamic response characteristics of shallow buried underground structures under different types of seismic waves are studied.The main achievements of this dissertation are described as follows:(1)The seismic wave input method based on the substructure of artificial boundaries is proposed.In the new method,the equivalent input seismic loads to implement the seismic wave input are obtained directly from the dynamic analysis of the substructure of artificial boundaries,which skips the tedious computational process of the wave method.The new method has high accuracy and the process of calculating the equivalent input seismic loads is simple,which make it easy to implement the seismic wave input.The validity of the new method is verified by the numerical examples of seismic analysis of the elastic half-space and layered half-space.(2)A multi-scale analysis method for seismic analysis of structures in near-source complicated sites is proposed.Through the analysis of large-scale epicenter-site model,the generalized free-field seismic motions are obtained,and the seismic analysis of the small-scale soil-structure model is conducted by the seismic wave input method based on the substructure of artificial boundaries.The effectiveness of the multi-scale method is verified by a numerical example.For the case in practical engineering that the global free wave field can't be obtained,a mixed wave field technique for seismic wave input is proposed.Combined with the seismic wave input method based on the substructure of artificial boundaries,the seismic analysis of the slope topography is conducted to verify the feasibility of the mixed wave field technique.(3)A more universally applicable method for seismic wave input——the seismic wave input method based on the internal substructure is proposed.In this method,the seismic wave input is transformed from the external source input problem into the internal source problem,making this method applicable to various artificial boundaries.Numerical examples verify the effectiveness of the new method.For the absorbing boundary consisting of damping layers,the seismic wave input method based on the internal substructure is verified.Besides,the combined artificial boundary is proposed to reduce the thickness of the absorbing boundary and improve the simulation accuracy.(4)By means of the seismic wave input methods proposed in this dissertation,the dynamic responses of a shallow buried underground structure under different incident angles of SV-wave and P-wave and Rayleigh wave are studied.The internal forces of the structure and the acceleration responses of the site are compared and analyzed.Besides,the distributions of the plastic hinges under large earthquakes are studied.Based on the numerical results,the dynamic characteristics of shallow buried underground strucutres under different types of seismic waves are summarized.