Research On The Deformation Characteristics And Gas Seepage Rule Of Coal Body Loaded By High Pressure Water

Based on the design about the “gas seepage experiment device loaded by high pressurewater” and the making of raw coal samples with “twice moulding” method successfully,experimental research on the rupture process under high pressure water and the seepage changerule before and after high pressure water loading is carried out. The rupture process, the criticalvalue of pressure water and the gas seepage rule before and after high water loading about twotypical raw coal samples(the original structure coal and the tectonic soft coal)are analyzed. Therelationship between crack ignition (extension) of coal samples and loaded axial pressure(confining pressure) is obtained by simulating with the equipment. Two through boreholes’(onefracturing object is the tectonic soft coal seam, the other is its hard roof)fracture plan are designed,field test investigation is carried out in Huaibei mining (Group) Co. Ltd. of Linhuan coal mine, thefracturing effect is observed with gas extraction concentration, gas flow and so on. Test resultsshow that the effect of hydraulic fracturing on the soft coal seam is very small, the laboratoryresults are further confirmed. To this problem, the paper points out that fracturing the hard roof ofthe soft coal seam can remove the gas pressure and increase the permeability. The field resultsshows that “roof fracture of soft coal seam” can increase the permeability of soft coal seam andimprove the gas drainage effect greatly.