Study on pressure relief prevention and control effect of hydraulic fracturing in deep pressurized working face
During the driving process of S5207 return airway in Yuwu Coal Industry,Lu'an Chemical Group,problems such as floor heave,top corner heave and roof subsidence occurred in some roadways,and there were dynamic manifestations such as broken anchor rods,cables,and sound coal cannons.The measurement showed that the maximum horizontal principal stress in the direction of N21.5° E was 9.15 MPa,the minimum horizontal principal stress was 4.97 MPa,and the vertical principal stresswas 10.9 MPa.In order to solve this problem,hydraulic fracturing technology was adopted for the S5207 deep pressurized working face to weaken the hard and dif-ficult to collapse roof.After the displacement,stress and load detection at the detection points in the fractured and non-fractured sec-tions,the results showed that in the fractured section,the proximity rate of the roof and floor and the shrinkage rate of the two sides were reduced by 43.8％and 37.9％,respectively.The stress value of the lagging working face in the fractured section remained stable at an average of 13.05 MPa,while the stress on the non-fractured section continued to increase,reaching a final average of 18.6 MPa.In the position of the advcance working face,the peak value of the advcance timbering stress appears in the working face of the fractured sec-tion,the average value was 13.0 MPa,the increase was 2.1 MPa,and the advcance timbering stress concentration coefficient was about 1.2.To sum up,the hydraulic fracturing technology can significantly reduce the coal winning dynamic pressure of adjacent working faces,reduce roadway stress and surrounding rock deformation,effectively weaken the hard roof,improve the overall safety of roadway,and ensure the success rate of roadway retention under dynamic pressure.The application of this technology not only solves the technical problems of the dynamic pressure roadway in Yuwu Coal Industry,but also obtains certain technical,economic and social benefits,and provides valuable experience for the pressure relief of the roadway under similar conditions.
deep pressurized working facereturn airwayhydraulic fracturinghard and difficult to collapse roof
万方数据
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