Advanced Pre-grouting Reinforcement for Geological Abnormal Zone at High Gassy Working Face

In order to solve the influence of F_j145 fault on mining. The ground stress state of geological abnormal zone was analyzed by ground stress test, and the formation reasons of normal fault, stress evolution laws and influence scope were analyzed by software FLAC^3D, and then the high pressure grouting was used for advanced deep hole reinforcement, the grouting pressure was 25 MPa. Modified cement liquid was developed, and the improved cohesion was 1.2 MPa between cement grouting and coal; the drilling speed and drilling hole paste were solved by improved drilling way. The grouting result was monitored by geological radar, the results show that the broken fault zone was renewed, and the grouting result was good.