ABSTRACT
Fault-slip induced by longwall mining is a significant cause of indirect coal burst. This paper summarises the results of a numerical modelling study using FLAC3D, in which a longwall face approaches a fault with different fault angles of 45°, 60°, 75° and 90°. Zero-thickness interface elements, which are capable of Coulomb sliding, were built in the numerical model to simulate the fault. The paper presents detailed parametric analysis of the influence of cover depth, friction angle of the fault plane, fault angle and approaching direction. Numerical results showed that these factors have a significant influence on shear stress drop, shear slip and the magnitude of seismic energy. In terms of fault behaviour during longwall extraction, shear stress on the fault plane above the coal seam first increased and then decreased when the longwall face was approaching the fault. The maximum magnitude of seismic events occurred when the longwall face was 15 m to 40 m away from the fault. Most seismic slip occurred on the fault plane above the coal seam with minimal movement below the coal seam.
