Effect of oblique incidence of SV waves on seismic response of portal sections of rock tunnels

By coupling the explicit finite element method with the viscous-spring artificial boundary condition, the formulae for calculating the equivalent nodal force under the oblique incidence of plane seismic SV waves are deduced. Then, the input of SV waves is realized in the FEM program. A half-space example with simple motion proves that the proposed approach has satisfactory precision. Subsequently, the proposed method is employed to investigate the rock tunnels with two oblique incidence conditions of cross section and vertical section. The numerical results indicate that under the action of obliquely incident seismic waves, the dynamic responses of rock tunnel are clearly different from those under the action of vertically incident seismic waves. In addition, the dynamic responses of the rock tunnels vary greatly with the incidence of SV waves in cross section and vertical section.