Abstract:
In view of the problem that the dynamic disaster caused by the overlying coal pillar in close distance shallow seam, based on the supporting concept of "caving fillings+overlying coal pillar", the technology of advanced weakening and treatment of roof staged fracturing was put forward combined with the technology of directional long borehole precise hole formation. Combined with the theoretical analysis, technology development, engineering practice and other methods,the principle of advanced weakening and treatment of roof stage fracturing was explored, and the engineering application was carried out in typical mine. The results show that in the stage fracturing construction process, the maximum injection pressure is 21.20 MPa, the maximum fracture pressure drop is 7.60 MPa, the pressure drop above 3.00 MPa occurres more than 50 times; compared with the unfractured sections, the periodic pressure step, dynamic load coefficient and maximum pressure are reduced by 13.58%, 13.77% and 25.49% respectively after fracturing, the effectiveness of fracturing technology is verified. The treatment technology can effectively control the dynamic disaster caused by overlying coal pillars.