Analysis Of Influence Of Anchor Spacing On Stability Of Surrounding Rock In Deep Coal Mining Roadway

With the coal mining exploration deeper,the original rock stress is getting larger and larger,and the surrounding rock conditions are becoming more complicated.The difficulty of supporting the roadway is gradually increasing.In the current coal roadway support,anchor cable support has become the most important support method.However,under different roadway lithology,roadway depth(original rock stress)and roadway section size,the reasonable array pitch between bolts and anchors is not the same.It is extremely important to seek reasonable array pitch between bolts and anchors under different conditions for the safety and economy of coal mining.From the angle of reasonable bolt support array pitch of the coal roadway side,this paper studies the reasonable bolt spacing of roadway gangs under different lithology,different roadway depths and different roadway sections via experiments and numerical simulation methods.In order to make the analysis process relatively simple and representative,the coal lithology takes hard coal,medium hard coal and soft coal;the original rock stresses are 10 MPa,14MPa and 20 MPa respectively and the section dimensions of the roadway are 4×3m,5×4m and 6×5m respectively.When studying the factors of lithology,the original rock stress and roadway size should be20 MPa,5×4 m;when studying the buried depth factor,the lithology and roadway size should be medium hard coal,5×4 m;and when the dimension factor of roadway section is studied,the lithology and original rock stress are taken from medium hard coal,20 MPa.Different bolt support spacing is represented by the coordinates in the numerical model.The specific values are indicated in the text.After numerical simulation using FLAC 3D numerical simulation software,the numerical results are obtained.And after importing the Tecplot processing software,the data is sliced and taken to obtain the data,then the data is sorted and analyzed by the Origin mainly based on displacement field and stress field analysis.Displacement field analysis includes displacement analysis and displacement gradient analysis;stress field analysis mainly includes analysis of arching coefficient and analysis of horizontal shear stress change of gang.The final conclusion is as follows:The lithology,depth and section size of the roadway are the most important factors affecting the stability of the surrounding rock of the roadway.Bolt support plays an auxiliary role in maintaining the stability of the roadway.It can maintain the stability of the roadway to a certain extent and control the deformation and fracture of the surrounding rock.The spacing of reasonable bolt support in different roadways is different.In general,the worse the lithology,the deeper the buried depth and the larger the size,the greater the bolt support density required for the roadway.For each factor,the reasonable bolt support spacing of the roadway gang is described in the text,which can provide a certain reference for the practical engineering.