Study On Failure Mechanism And Repair And Reinforcement Of Surrounding Rock Of Double Wing Mining Roadway Group

The Beida roadway group in Qipanjing Coal Mine is disturbed by many times by the supporting stress of the adjacent roadway project and the double-wing mining face in Beipan District.The stress environment of the roadway surrounding rock is bad,and the deformation and destruction are serious,which seriously threatens the safety of the mine production.At present,there is insufficient understanding of the propagation law of supporting stress in double-wing mining face and the control principle and technology of surrounding rock in high dynamic pressure roadway,and the control technology of surrounding rock in roadway is unreasonable.Therefore,based on the research background of Beida roadway group in Chepanjing Coal Mine,this paper systematically studies the deformation and failure characteristics and repair and reinforcement technology of double-wing mining roadway group by means of on-site investigation,indoor experiment,theoretical analysis,numerical simulation,on-site test and industrial test,and obtains the following main research results:(1)Summarized the characteristics of surrounding rock deformation of Beida roadway group under the condition of double-wing mining in Qipanjing Coal Mine:large amount of roadway deformation,fast deformation and long duration;diversified forms of roadway deformation and destruction;high pressure of roadway surrounding rock and large number of failure of support structure.On this basis,the influencing factors of surrounding rock deformation and failure are determined: large-scale,high-strength mining stress repeated influence;in-situ stress;stopping line location;support mode;other comprehensive factors.(2)It is revealed that the continuous reduction of surrounding rock conditions caused by repeated disturbance of mining support stress is the fundamental external factor leading to the deformation and destruction of surrounding rock of Beida roadway group.During single-wing mining,mining support stress leads to the increase of deformation of surrounding rock of Beida roadway,which is characterized by roof subsidence and two-sided migration.Stress environment and surrounding rock conditions have not deteriorated significantly.The deformation of surrounding rock of roadway is large but consolidated.During the period of double-wing mining,the supporting stress caused the rapid increase of surrounding rock deformation of the whole roadway group,which manifested as rapid roof subsidence and significant movement of both sides,deterioration of stress environment and surrounding rock conditions,failure and instability in part of the roadway position,and sharp decreaseof overall stability.(3)Put forward the principle of repairing and reinforcing surrounding rock of roadway group: adopting the combination form of "shallow hole grouting + high strength yielding bolt",forming inner ring reinforcing layer with certain thickness and flexibility in the shallow fracture area of roadway surrounding rock;adopting the combination form of "deep hole grouting + high elongation yielding anchor cable" to reinforce deep surrounding rock,and cementing deep fractured rock mass into a whole by grouting fluid to improve rock mass.Physical and mechanical properties,forming the outer ring reinforcement layer.The coordination of inner and outer reinforcement layers jointly ensures the overall stability of the roadway.(4)The intrinsic properties of grouting fluid are studied in terms of its flow state and diffusion range,grouting parameters and grouting pressure.The mechanism of grouting reinforcement on roadway surrounding rock properties is studied in detail,and the essence of grouting improvement on roadway surrounding rock is revealed.Based on the classification of Roadway Groups and the core of reinforcement layer of inner and outer circles,the technical system of repairing and reinforcing surrounding rock of double-wing mining roadway groups is put forward.(5)The repair and reinforcement technology based on the design principle of inner ring reinforcement layer formed by high-strength yielding bolt and shallow grouting and outer ring reinforcement layer formed by deep grouting is developed.Reasonable bolt support parameters,grouting parameters and construction technology are designed to better guide production practice.There are 58 figures,22 tables and 81 references in this paper.