Numerical simulation on failure effect of mining-induced dynamic loading and its influential factors

Abstract

Rock burst, a serious seismic hazard in underground coal mining, is usually induced by the coupling effect of static stress and mining-induced dynamic loading. This paper chosen an underground longwall face (LW10302) in Baodian Coal Mine as the numerical simulation model, selecting measured tremor wave which located about 150 m above the goafing of LW10301 as dynamic source, and the failure effect of dynamic loading on coal seam entry and its influential factors can be simulated systematically by FLAC3D. By changing source energy, source location, coal-rock property, the simulation results show that failure effect of dynamic source is more sensitive to source location, followed closely by source energy, and then the rock property. That is, dynamic disturbance is deeply influenced by source location, which is decreased in exponential attenuation with the increasing of transmission distance, while it also increases largely with the source energy increasing. Meanwhile, Burst effect of dynamic source can also be reduced duo to rock integrity reduction and intensity weakening, which the corresponding dynamic loading can be decreased to even less than 40%, but the influence degree may be reduced in the condition of shorter transmission distance. Moreover, the occurrence of rock burst also depends on static stress field around the coal face. Thus, the corresponding measures should be carried out simultaneously to reduce the disturbance effect of dynamic source and static stress concentration. The conclusions can provide theoretical reference to rock burst controlling in underground mining.