3-D Scattering Of Incident Plane SV Waves By Twin Cavities In Layered Space

There is a significant amplification on the incident seismic waves by twin cavities. Therefore, carrying out research work for this issue has an important theoretical significance, and also for guiding the work of dividing the earthquake areas. However, most previous studies are assumed that the soil is homogeneous elastic half-space and the research for this problem is limited to the frequency domain analysis. Actually, the natural soil is layered, so the layered medium model is needed to reflect the soil's inhomogeneous along the depth direction. This article is the study in frequency and time domain of SV waves by twin cavities in layered elasticity half-space.Based on the three-dimensional dynamic stiffness matrix, three-dimensional Green's function, it analyses impact of the double tunnel by SV wave's incident in frequency domain and time domain. In frequency domain, it researches the surface displacement amplitude in incident horizontal angle changed, the stiffness ratio between bedrock and soil changed and the changes in soil thickness. About time domain, it studies from the part of incident Ricker wavelet and seismic waves.The results show that there are many parts influence the surface displacement amplitude. As the incident wave's frequency increasing, the displacement amplitude gradually becomes complicated and decreasing overall. As the stiffness ratio between bedrock and soil increasing, the displacement amplitude is increasing as well, and when the incident wave's frequency is closer to the resonance frequency, this trend will be more obvious. As the soil thickness increasing, the displacement amplitude is gradually decreasing. When the tunnels are getting closer, the interaction between them will be greater.