层状半空间中洞室对入射平面SV波的散射

利用间接边界元法，在频域内求解了层状弹性半空间中洞室对入射平面SV波的散射问题。通过自由场反应分析，求得假想洞室边界上各点位移和各单元应力响应。在洞室边界各个单元上施加虚拟分布荷载，求得位移和应力的格林函数。根据应力边界条件确定虚拟分布荷载，将自由场位移响应和虚拟分布荷载产生的位移响应叠加起来，即得到问题的解答。比较了层状半空间和均匀半空间中洞室对入射平面SV波的放大作用。结果表明，层状半空间情况有可能导致较大的地表位移幅值，尤其是对于较低频率入射波。

Scattering of plane SV waves by a cavity in a layered half-space

Scattering of SV waves by a cavity in a layered half-space was analyzed by indirect boundary element method in frequency domain. The free-field displacements and stresses were calculated on the line which will form the surface of the cavity. Then fictitious distributed loads were applied on the same line to calculated Green’s functions for displacements and stresses. The amplitudes of the fictitious distributed loads were determined by the boundary conditions, and the displacement response arising from the waves in the free field and from the fictitious distributed loads were then summed up to obtain the solution. The amplification of the incident SV waves by a cavity in a homogeneous and a layered half-space were compared; and numerical results showed that larger surface displacement amplitude may be resulted in the case of layered half-space, especially for low-frequency waves.