Research On The Withdrawal Process And Roof Control Technology Of Self-cutting Withdrawal Channel

With the continuous improvement of coal mine modernization and the steady improvement of coal mine production capacity,coal enterprises have higher requirements for the rapid continuation of fully mechanized mining face.More safe and efficient fully mechanized mining face withdrawal process has become the exploration trend of the coal industry.Due to the unreasonable layout of withdrawal channel and support technology,safety accidents such as the reduction of recovery rate of fully mechanized mining face,roof subsidence during equipment withdrawal,pressure frame of hydraulic support in working face and partial roof falling are caused,which endanger the mine safety production.Taking 1108 working face of Yidong Coal Mine in Shaanxi Province autotomy retracement passage shelves as engineering background,using FALC3 D numerical simulation and theoretical analysis,field monitoring,such as integrated research methods,to cut retracement from channel at the end of the roof deformation and failure law is analyzed,compared to puts forward the optimization scheme and retreat of roof control technology,the main research contents and results are as follows:(1)The geological conditions of the drawback working face are systematically studied.According to the support design of mining and excavating face of Yidong Coal Mine in Shaanxi Province,the roof support parameters of symmetrical,linear and asymmetric self-cutting drawback channel are proposed,and the support parameters are checked according to the suspension theory to determine the rationality of the support scheme.The numerical model of self-cutting drawback channel was established,and FLAC3 D numerical simulation software was used to simulate and analyze the roof stress and displacement at different lengths under three supporting modes of self-cutting drawback channel.The results show that the roof stress,displacement and axial force and displacement of the support structure are significantly reduced by using asymmetrical support mode,and the bolt row distance of the side far from the solid coal wall is reduced.(2)According to the custom retracement channel of roof structure,retreat channel under different supporting method of mechanics model is set up,by applying uniform force mechanics model retracement channel section of the roof,linear,asymmetric forces,respectively to simulate support in symmetry,linear supporting,supporting roof stress distribution under the condition of asymmetric,and three different supporting was deduced under the condition of roof subsidence relation.The results show that the maximum amount of roof subsidence is located at the side far away from the solid coal wall under the condition of unsymmetrical support,and the control of roof subsidence is more effective than the other two support methods.(3)Based on the situation of 1108 withdrawal working face of Yidong Coal Mine in Shaanxi Province,the net hanging process,withdrawal process and support process of quick stoping at the working face under the condition of self-cutting withdrawal channel were formulated.On the basis of numerical analysis and theoretical calculation,the cooperative operation of shearer cutting and working face support under asymmetric support mode is analyzed,and the technical parameters such as row distance between asymmetric support of anchor bolt(cable)are studied.(4)Field application industrial test was carried out in combination with self-cutting retreat channel of 1108 fully mechanized mining face in Yidong Coal Mine,Shaanxi Province.Through monitoring the roof pressure and the amount of roof separation at the end of working face mining stage,using bolt dynamometer and roof separation meter to monitor the roof pressure and roadway surface displacement of the full length of the withdrawal channel.By analyzing the concentration of roof pressure and the control of roof subsidence in asymmetric support mode,the continuous stability of 1108 fully mechanized mining face retreat space is realized,and the mine safety and efficient retreat are guaranteed.Figure [59] Table [4] Reference [92]...