Study On Surrounding Rock Control Technology Of Supporting Top Coal Roadway In Wantongyuan Mine

Taking the stability control of surrounding rock of the supporting coal roadway of Wantong source mine as the research object,the paper establishes the mechanical structure model of composite roof by using the field measurement,theoretical analysis and numerical simulation,analyzes the factors and rules affecting the stability of the surrounding rock of the supporting coal roadway,and makes a reasonable support scheme,and has been successfully applied in the engineering practice of Wantong source mine.The main research results are as follows:(1)The mechanical parameters of coal seam and roof coal are measured by the method of mechanical properties test in the room,which provides the basis for theoretical analysis and numerical simulation.(2)The mechanical structure model of composite roof is established.Under the condition of composite roof,the calculation formulas of deflection,separation between layers and critical load of delamination instability are derived respectively.Various factors(lane width,overburden load and elastic modulus)of surrounding rock stability of roadway are analyzed.The following laws are obtained:(1)the fourth order of roof subsidence is proportional to the width of roadway The system,that is,the large section will increase the subsidence and separation of the roof,and the stability of the roof will decrease;(2)the load of the overlying rock and the deflection of the layer are linear,and the deflection increases linearly with the increase of the layered load;(3)the deflection of the roof layer decreases with the increase of elastic modulus;(4)the bolt(cable)support can effectively increase the thickness of the layer in the composite roof roadway,and inhibit the roof subsidence Separation of the layer,enhance the stability of the roof.(3)With FLAC3 D finite difference software,the paper analyzes the evolution law of roof prestress under different supporting parameters of coal roadway,and determines reasonable supporting parameters.The bolt adopts left-hand non longitudinal reinforcement threaded steel bolt with diameter of ? 22 mm,anchor rod length of 2.2M,spacing × row distance(0.8m × 0.8)The layout of the anchor cable of the roof of the track Lane,the North track Lane,the transportation lane and the North transportation lane is 1600 mm,with one or two connection arrangements in each row;the layout of the anchor cable of the roof of the return air lane is 1600 mm,and one or two of each row is arranged;the layout of the anchor cable on the top plate of the North return air roadway is 1600 mm,and one or two joints are arranged in each row.(4)The industrial experiment results show that the convergence value between the top and the bottom of the roadway is about 67 mm,the relative displacement between the top and the bottom plate is about 47 mm,the maximum departure value of the roof anchorage area is about 13 mm,but it is still within the boundary of the roof separation of the roadway roof,and the roof is relatively stable and safe.The maximum load of the anchor rod is about 127 kn,and the maximum axial force of the anchor cable is about 185 mm Kn,the anchor(cable)still has bearing capacity,which verifies the control effect of bolt(cable)support scheme on the deformation of surrounding rock.There are 51 pictures,8 tables and 83 references in this paper.