| With the rapid development of China’s economy and the continuous growth of the population,China’s underground structure construction has also developed rapidly,so the seismic analysis of underground structure has been widely concerned by the academic community.However,previous seismic analysis of underground structures usually assumed that seismic motion propagated upward from bedrock in a direction perpendicular to the surface and was applied to underground structures.In fact,seismic waves generated by shallow earthquakes were likely to be incident into underground structures at a certain angle with the vertical direction.Based on the viscoelastic boundary theory and the equivalent nodal force method of seismic waves,the dynamic responses of subway double tunnels and subway stations under oblique incidence of seismic waves are analyzed in this paper.The main results are as follows:1.Based on the viscoelastic boundary theory and the equivalent nodal force method,programmed the equivalent nodal force of 2D and 3D input script with Python,and according to the status that current academic circles have not agree on one decomposition method of wave field of viscoelastic boundary theory yet,summed up three kinds of commonly used decomposition method of wave field and compared the precision by numerical simulation analysis,and finally found the third decomposition method of wave field has the best calculation precision.The wave decomposition method was used for subsequent analysis.2.According to a double tunnel condition of subway in a city,established a 2D finite element model in ABAQUS,used the equivalent nodal force exerting script to put the P wave and SV wave to the model.The results show that with the increase of P wave oblique incidence angle,the dynamic response of the tunnel wasn’t changed obviously,and as the increase of oblique incidence angle of SV wave,the dynamic response of the tunnel was significantly increased.3.According to the actual condition of a subway station in a city,established 3D finite element model of the main structure of the subway station in ABAQUS,used the equivalent nodal force exerting script to put the P wave and SV wave to the model.The results show that the axial force and shear force of the top of pillars decreased with the increase of P wave input angle,and increased with the increase of SV wave input angle,so the oblique incidence of SV wave in the subway would damage more to the structures of subway station than the oblique incidence of P wave. |
