Fracture Effect of Coal Permeability Changes in Stress Concentration Belt

Based on the coal fracture mechanics analysis and numerical simulation results, we proposed that fractures secondary "on-off" caused by mining stress concentration affected permeability changes in front of the coalface, and led to the increase of the permeability in stress concentration belt. The article discussed the permeability change laws of the coal with fracture in stress concentration belt and three types of fracture evolution, which guided the prediction of coal permeability change. Taking the fractured coal as an example, through the field observation of fracture evolution, the article verified the permeability change laws in stress concentration belt.