Mechanism of coalburst triggered by thrust fault slipping based on field monitoring, indoor experiments and numerical simulation

Abstract Coalburst disasters induced by thrust fault slip frequently take place in underground coal mines and often lead to severe roadway damage and personnel casualties. However, the triggering mechanism of coalburst remains unclear. Combined with field monitoring, physical analog simulation and numerical simulation, this study identifies the segmented slip behavior of thrust faults induced by mining activities, reveals the formation mechanism of stress concentration in coal bodies between mining panels and the fault, and analyzes the generation sources of dynamic stress disturbance. Furthermore, laboratory coupled static-dynamic loading tests are carried out on hollow coal specimens simulating underground roadways, and the progressive damage and failure characteristics of coal are investigated. The main conclusions are as follows: (1) As mining advances toward the thrust fault, the fault exhibits obvious segmented slip: the upper fault segment slips anticlockwise while the lower segment slips clockwise. (2) The clamping effect generated by segmented fault slip is the primary factor inducing high stress concentration in the coal between the working face and the thrust fault. (3) Coal bodies bearing high static stress are highly susceptible to unstable failure and subsequent coalburst under superimposed dynamic stress loading. (4) Tensile stress waves reflected at roadway surfaces break surrounding rock, triggering coalburst accompanied by sidewall spalling and floor heave. (5) Segmented fault slip and its resultant clamping effect are two core factors responsible for thrust fault-slip coalburst. This paper puts forward a new viewpoint that segmented fault slip acts as the fundamental trigger of thrust fault-slip coalburst, which provides an in-depth theoretical basis for revealing the occurrence mechanism of such coalburst disasters.