Sensitivity analysis of roadway surrounding rock deformation factors under dynamic disturbance

The surrounding rock of the underground tunnel is more likely to to be deformed or even unstabledue to dynamic disturbances such as fracture of overburden, blasting and excavation of rock roadway in coal mining under high ground stress.Based on the elastic theory and stress wave theory, the mechanism of tunnel surrounding rock instability under disturbance is analyzed. The ideal elastic-plastic model of roadway surrounding rock is established by FLAC3D software. On the basis of orthogonal optimization combination, the sensitivity analysis of factors (peakstress, frequency, lateral pressure coefficient and disturbance time) affecting roadway surrounding rock deformation under dynamic disturbance is carried out.The results show that different influencing factors have great differences in the sensitivity of the maximum displacement of roof and ribs of the tunnel;By analyzing the deformation under 16 different combinations, it is found that the deformation degree of roof and sides is the greatest when peakstress is 20 MPa, frequency is 1 Hz, lateral pressure coefficient is 1.4, disturbance time is 0.8 s, the deformation degree of roof and sides is the lowest whenpeakstress is 5 MPa, frequency is 15 Hz, lateral pressure coefficient is 0.8, disturbance time is 0.2 s. The sensitivities that affect the deformation of roof and sidesare in the order of lateral pressure coefficient, disturbance time, peakstress and frequency. Finally, a multiple linear regression analysis method was used to establish the mathematical formulas of roof and slab deformation under the action of multiple factors. The regression effect is very remarkable, which provides engineering reference for the effective support of roadways