Mechanical model for the calculation of stress distribution on fault surface during the underground coal seam mining

Abstract The instability caused by the fault slip is one of the main factors that induce the occurrence of coal bursts. To in-depth understand the mechanisms responsible for coal bursts during the underground coal seam mining, a mechanical model used to calculate the stress distribution on fault surface and illustrate the fault slip characteristics is proposed by considering the mining-induced stress. In order to verify the validity of this model, a set of comparative analyses with experimental results which have been published in the previous studies are carried out. The results show that the normal and shear stress distribution on the fault surface calculated by the mechanical model is approximately consistent with the experimental stress results. According to the calculated stress distribution on the fault surface, normal and reverse faults formation mechanism are explained by this mechanical model when the lateral pressure coefficient is greater than 1.0 and less than 1.0. Meanwhile, fault potential energy is proposed to research the energy storage and further explain the mechanism of fault slip. In addition, the coal bursts occurrence induced by fault slip is also discussed according to the engineering background and this mechanical model.