Influence of faults on coal roof stability by physical modeling study

Through simulation test of similar materials,the distribution of deformation failure and underground pressure with high-angle faults of different dip direction are analyzed during coal mining operation.The results indicate that roof rock-mass in fault zone and its influential range is broken and with poor stability by activation of fault after coal mining,so the distance of periodic weighting decreases and the caving zone increases,particularly in the footwall of fault.When working face is mined about 22.5 to 30.0 m to the fault,the abutment stress ahead of working face obviously increases,coal seam is crushed,and the peak value of abutment stress migrates to the inside of rocks(coal) with reduction of distance away from the fault.Compared with non-fault,the abutment stress of the foor rock mass decreases after passing the fault.