Dynamic stress concentration factor for tunnel surrounding rock under blasting seismic waves

The blasting seismic waves are simplified reasonably. Based on the wave function expansion method, an equation for dynamic stress concentration factor of tunnel surrounding rock of infinite rock under the blasting seismic waves is deduced. Based on a typical case, the influences of the main frequency of the blasting seismic wave and the physico-mechanical indices of tunnel surrounding rock on the dynamic stress concentration factor at different positions are quantitatively analyzed. The results show that the dynamic stress concentration factor of tunnel surrounding rock near blasting is larger than that far away from it. The peak of dynamic stress concentration factor of tunnel surrounding rock is close to the near-blasting side. There is a peak of the dynamic stress concentration factor under different main frequencies of the blasting seismic waves. The elasticity modulus of the surrounding rock has a greater effect on the dynamic stress concentration factor, and the effect of Poisson's ratio of rock on the factor can almost be neglected.