SV波入射情况下V型河谷地形对地震动的影响分析

基于局部人工边界的显式有限元方法,给出了二维V型河谷地形在SV波垂直人射下地面运动数值解,并分析其地震动分布规律以及两侧不同的边坡角度对于地震动分布规律的影响.数值结果表明:谷底的角点、两岸靠近河谷的点、两侧谷坡靠近谷底的点以及靠近两岸的点,对地表位移有放大作用,而对其邻近区域地表位移有抑制作用.这是由于角点处存在面的...

Influence of V-shaped canyon site on ground motions for incident SV waves

A numerical solution to the 2D model of V-shaped canyon under the normal incident SV waves is derived by using the explicit finite element combining local artificial method,and the distribution rule of site ground motions and the effect of different slope angles on influence range of bank PGD are discussed.Based on the numerical results,it is found that the surface ground motions at the intersecting positions of valley bottom and the slope,the slope and the bank are great while the adjacent regions of these points is constrained.This may be due to the scatter of the SV wave and the wave-type conversion is rather complicated at the intersecting positions.And the closer to the intersecting position,the stronger the scatter waves appear.The rules above are proved by the results of PGD,amplitude of transfer function and particle motions.The wave-type conversion of the right bank and the right slope top is greater than that of the left side,and the influence range of the left bank is larger than that of the right bank,because the right slope angle is larger than that of the right side.The particle motion coda on both sides of the bank is viewed as the backward motion,and the backward elliptical motion of some observation points are very obvious.These calculations predict that at the bank on both sides the normally incident SV wave may be converted into Rayleigh wave.