| The support technology of soft rock roadway has always been a key problem in coal mining.Due to the characteristics of low strength and poor stability of surrounding rock,soft rock roadway excavation and mining support are very difficult,which are characterized by short self-stability time of roadway,easy creep,large deformation of roof,floor and side,and long duration of deformation.The 110207 soft rock roadway in Maiduanshan Coal Mine encountered a wide range of deformation and failure problems,such as cement,roof breakage,and so on.The original support scheme could not meet the mine production demand,and the anchor cable grouting reinforcement provided an effective way to solve the support problem of soft rock roadway.Therefore,it has important research and engineering significance to study the grouting anchor cable reinforcement technology and field application of 110207 soft rock roadway in Maiduo Mountain Coal Mine.Based on the 110207 return roadway of Maiduanshan Coal Mine as the research background,this paper studies the failure characteristics and instability factors of110207 soft rock return roadway by using theoretical analysis,physical experiment,numerical simulation and industrial application,and reveals the reinforcement mechanism of grouting anchor cable and the law of grout diffusion in soft rock roadway.The influence of different grouting anchor cable reinforcement schemes on roadway surrounding rock deformation is simulated,and the best supporting scheme suitable for the roadway is obtained,and the industrial application is carried out.The main conclusions are as follows:(1)Failure characteristics and instability factors of 110207 soft rock return roadway are studied.Through the field investigation and laboratory test analysis,it is found that the sandstone aquifer in the lower part of Zhiluo Formation in coal roof of No.11 mining area 2 has strong water-rich and large thickness,the roadway deformation is obvious,the roof subsidence and floor heave increase,the rock formation lithology changes dramatically,and the supporting effect of the roadway on site is poor.Soft rock roadway is affected by cement and roof clay anchorage is weak.(2)The mechanical reinforcement mechanism of grouted anchor cable on soft rock is analyzed,and the key parameters of grouted anchor cable grout diffusion are determined.COMSOL simulation software was used to simulate the diffusion and penetration law of 110207 roadway roof,and the influence of key parameters such as grouting time,grouting pressure and grout water-cement ratio on grout diffusion radius of anchor cable was simulated.The influence of grouting anchor cable on the mechanical properties of broken surrounding rock is studied.The grout between grouting anchor cables does not penetrate and only diffused around the anchor cables.(3)FLAC3D is used to obtain the best support scheme suitable for the roadway.The surrounding rock stress,plastic zone and displacement evolution law of soft rock roadway under different grouting anchor cable support schemes are compared,and the grouting reinforcement support technical scheme of roadway is determined,that is,the supporting method of bolt,short anchor cable and grouting anchor cable in scheme five can effectively play the bearing capacity of supporting members.(4)The industrial test results show that after the implementation of the grouting anchor cable scheme,the roadway deformation decreases significantly,and no obvious separation layer is found in the development of internal cracks except for the influence of mining stress.The grouting anchor cable plays an active supporting role,improves the overall supporting strength of the roadway surrounding rock,and ensures the stability of the 110207 soft rock return roadway in Maiduanshan Coal Mine.There are 48 figures,5 tables and 73 references in this paper. |
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