Study On The Mechanism And Control Technology Of Deformation And Instability Of Surrounding Rock In Deep Rectangular Coal Roadway Of Wanfu Mine

The deep rectangular coal roadway has the characteristics of large buried depth,high stress concentration and poor stability of surrounding rock,and its support control problems need to be solved urgently.Therefore,this paper takes the transportation roadway of 1305 working face of Wanfu Coal Mine as the research object,combined with the field engineering geological conditions,and adopts the methods of field survey,theoretical analysis and numerical simulation to analyze the surrounding rock stress distribution law and deep coal seam of the rectangular roadway The deformation and migration mechanism of the roadway has designed a reasonable support scheme for the site and verified the feasibility.The main conclusions of this paper are as follows:(1)Based on the theory of complex variable elasticity,the mapping relationship from rectangular coordinate plane to complex plane is established,and the theoretical expression of surrounding rock stress around rectangular tunnel is deduced.The influence of lateral pressure coefficient and width height ratio of tunnel on the distribution of maximum tangential stress of surrounding rock around rectangular tunnel is analyzed.(2)By using the method of numerical simulation,the influence of the depth of roadway,the horizontal stress of roadway,the width of roadway and the thickness of top coal on the surrounding rock failure of deep rectangular coal roadway in Wanfu mine is analyzed.Under different buried depth conditions,the stress peak value and shear stress concentration coeff-icient increase with the increase of buried depth.Under the action of high-level stress,the surrounding rock of the roadway shows soft rock property and large deformation.The amount of roof subsidence,side displacement and floor heave increase rapidly,which is approximately exponential growth.With the increase of roadway width,the amount of roof subsidence,the amount of side movement and the amount of floor heave are increasing,which are approximately linear growth.When no top coal is left,the curve of roof subsidence changes approximately linearly,and the slope of the curve basically remains unchanged;with the increase of top coal thickness,the roof subsidence increases sharply,and the subsidence deformation rate also increases significantly,and the subsidence deformation rate of top coal is greater than that of basic roof strata.(3)The support scheme of long bolt+long anchor cable is designed.The support simulation results show that the support scheme effectively controls the deformation of surrounding rock and the expansion of plastic zone.The maximum subsidence of roof is reduced by 81.4%,the maximum displacement of roadway side is reduced by 73.1%,the maximum floor heave of roadway is reduced by 40.5%,and the deformation and damage of roadway surrounding rock are effectively restrained by the support.The plastic zone of surrounding rock is greatly reduced after the support The main failure mode of roadway surrounding rock is shear failure,and the support scheme is feasible.There are 38 figures,16 tables and 124 references in this paper.