Analytical Solution of a Tunnel Within the Saturated Poroelastic Medium Subjected to Cylindrical P‐ and SV‐Waves

Dynamic analysis of tunnels under blast‐induced waves is crucial in civil engineering. Previous studies have often treated incident waves as plane waves, which may not be appropriate for the scenario of a wave source near the tunnel. In this study, the scattering of a tunnel in a saturated medium by cylindrical P‐ and SV‐waves is investigated. Based on the wave function expansion method, the displacement, velocity, pore pressure and stress fields over the substrate are determined. Some important quantities, including the dynamic stress concentration factor (DSCF), hoop velocity scaling factor (HVSF) and radial velocity scaling factor (RVSF), are evaluated and discussed. Numerical examples are carried out to discuss the effects of seepage boundary condition, type of incident wave, distance of the wave source and wave frequency on the distributions of DSCF, HVSF and RVSF. It is seen that the DSCF pertinent to the impermeable boundary condition is larger than the counterpart under the permeable boundary condition. In addition, the DSCF induced by the plane P‐wave may be smaller than that by a cylindrical P‐wave at low frequencies. This research is valuable for evaluating the safety of underground facilities under blasting waves.