Study On The Timing Of Hydraulic Fracturing In Advanced Stress Concentration Section Of Mining Face

Aiming at the problem that the pressure relief timing of the advanced stress concentration section of the coal mine fully mechanized coal mining face is large,which seriously affects the effect of roof cutting and pressure relief,the 3310 working face of Wangpo Coal Mine in Tiandi,Shanxi Province is taken as the engineering background,and the actual measurement working face of the hollow inclusion is used.The method of three-dimensional mining stress change in the roof of the leading section reveals the principle stress deflection rule of the leading section of the roadway during the face mining process,and proposes the concept of the best timing for cutting and pressure relief when the maximum principal stress deflection is at the smallest angle with the axis of the tunnel The hydraulic fracturing and decompression time of 3310 working face is 80¹50m ahead of the working face.The FLAC^3D numerical simulation software was used to calculate and analyze the principal stress evolution rule of the leading stress concentration section of the three working face layouts of single lane,double lane,and goaf remaining lane,and the pressure relief timing of the leading stress concentration section of the working face under single lane layout was obtained.It is100-200m ahead.The pressure relief timing in the double-lane layout is 80-140m ahead.The pressure-relief timing in the advanced stress concentration section of the working face along the empty-lane layout is 100-200m.Based on the research conclusions of numerical simulation and on-site monitoring,the typical working face was selected for the field test of hydraulic fracturing cutting and pressure relief,and reasonable pressure relief timing and parameters for greatly improving the pressure relief effect were proposed,which enriched the hydraulic fracturing cutting and pressure relief.Theory and technology.