The BEM Parallel Simulation Of Seismic Amplification Effect Of Three-Dimensional Complex Site And Software Development

Local site will change the characteristics of seismic waves,in which the sedimentary basin and mountain terrain are coupled,which makes the scattering of seismic waves more complex and endangers the safety of local personnel and facilities.The study of seismic wave scattering from complex sites is of great significance in practical engineering project and academic research.In the Wenchuan earthquake,Gansu Province is the hardest hit area after Sichuan Province.Therefore,based on the indirect boundary element method(IBEM),this paper studies the scattering of seismic waves in Chengguan Town,Wen County,Longnan City,Gansu Province,so as to provide scientific guidance for the earthquake resistance and disaster prevention work in this area in the future.At the same time,considering the unfriendly behavior of foreign software to Chinese users and the backwardness of ground motion simulation software in the domestic market,this paper develops a three-dimensional complex site ground motion simulation and analysis software based on indirect boundary element method,which actively responds to the cause of seismic fortification in my country.The main work is as follows:1.The indirect boundary element method is used to simulate and analyze the threedimensional large-scale basin mountain coupling terrain.To improve the computational efficiency of model with large calculation area,the GMRES algorithm is processed in parallel to speed up the calculation in the frequency domain.Through the comparison between hemispherical basin and intermountain basin model,it is verified that the impact of mountains on the basin can not be ignored,and the actual characteristics of the site should be respected in the subsequent simulation.2.Taking Chengguan Town of Wen County as the research area,the scattering of seismic waves by the topography of intermountain basin is studied.According to the data of landform and formation lithology in the study area,the modeling and meshing are carried out,and the indirect boundary element method is used for ground motion simulation.The frequency domain results are compared with the site monitoring data to verify the feasibility of the method and model,and the frequency domain and time domain analysis is given.3.The ground motion simulation and analysis software is developed based on Qt.The core algorithm adopts the indirect boundary element method and supports Open MP parallel computing.The developed software is aimed at windows and Linux systems.In order to improve the applicability of the software,each module can run independently.The research shows that the seismic response of the observation points located in the sedimentary basin in Chengguan town is more significant than that on the mountain,and the observation points reach the maximum seismic amplification effect in the low,medium and high frequency range.In the time domain analysis,the peak value of displacement time history of observation points in the basin is larger,the duration of strong earthquakes is longer,and the ground motion response is stronger.