Abstract: Based on the elastic damage mechanics theory, a piecewise linear and elastic damage constitutive model incorporating the residual strengths under different confining pressures was constructed, and the model parameters were determined by general triaxial compression and split tension tests. In addition, taking the geology conditions in one mine as engineering background, the damage and failure evolution characteristics of faulty coal seam floor during the mining process were simulated, after the established damage model programmed by MATLAB being embedded into COMSOL. The results show that when the working face moves to the top zones of fault, the active zones of fault will connect with the failure zones in floor induced by mining, which dramatically increases the failure depth of floor, reduces the water isolating properties of the aquifuge, and increases water-inrush possibility. Finally, the high-precision microseismic monitoring technique was employed to monitor the dynamic failure characteristics of the coal seam floor, and the monitoring results are basically in agreement with the numerical results.

Key words: fault activation, damage evolution, micro seismic monitoring, water-inrush