Effect of stress waves on fault slip using photoelastic analysis and numerical simulation

In coal mines, fault slips are often affected by stress waves originated from rock fracture during mining, but the effect of stress waves on a fault slip is still unclear. To understand such an effect, photoelasticity experiments and numerical simulation were carried out in this study, based on the thrust fault F16 in the Yima coal field, China. Three factors including stress wave sources, stress wave energy, and static friction coefficients of the fault were considered. The results show that: (1) Sources of stress waves located in the lower strata can more likely trigger the fault slip. (2) The curves of sliding displacement, strain ratio $r_{\epsilon }$ (shear strain to normal strain), and stress ratio $r_{\sigma }$ (shear stress to normal stress) of the upper fault are similar to “U” shape with increasing stress wave energy. The rock failure in the upper fault could be the reason of the rising curves when the stress wave energy is high. (3) Normal and shear stresses have different responses to the perturbation of stress waves. (4) More friction energy but less sliding displacement is induced by stress waves if the static friction coefficient of the fault is large. (5) The Mohr's circle of the fault can reach the Coulomb failure threshold if the energy of stress waves is high enough, resulting in fault slip.