Response of Tunnels to Incident SH-Waves

The two-dimensional scattering and diffraction of plane-state SH-waves by a circular tunnel in a homogeneous elastic half space has been analyzed. Using the series solution of the problem for a general angle of wave incidence, stresses and deformations near the tunnel have been studied. Their amplitudes have been demonstrated to be dependent upon the following parameters: the angle of incidence, ratio of the tunnel thickness to its diameter, ratio of the shear moduli of its wall to that of its surroundings, and the ratio of its depth to its diameter. The incidence angle determines the overall trends of the amplitudes. Higher frequency incident waves lead to greater complexity of the computed amplitudes. Stiffer tunnel leads to higher stresses on the outer tunnel surface. Perturbations of surface displacement amplitudes, which result from wave interference between tunnel and stress-free half-space surface, diminish with increasing depth of tunnels.