Numerical simulation study on failure characteristics of coal-rock combination with fracture

摘要

This paper studies characteristics of deformation failure and fracture growth of fractured coal-rock combination with RFPA2D numerical analysis software. Peak strength of the combination increases with increase of the dip of fracture and the peak strength when dip of fracture is 90° approaches to the peak strength without fracture. Under the same dip of fracture, peak strength of the combination when fracture is in the rock is higher than that in the coal, and fracture in the coal has more significant effect on the strength of the combination than in the rock. If fracture locations in combination are different, the characteristics of fracture growth are different. If dips of fracture in the same location are different, the fracture growth characteristics are different, too. However, fracture growth connection in coal is the main cause of overall failure of the combination body. During the loading, sound emission appears in two ends of fracture and the new fracture in the rock in upper end of the fracture, which mainly is caused by tensile failure. While in the coal, the new fracture in the end of fracture is caused by tensile failure; failures in other part are caused by both tensile failure and shear failure.