Study On Distribution Characteristics And Control Of Deviatoric Stress Field In Surrounding Rock Of Deep Coal Roadway

Coal is the main fuel for my country’s energy consumption.At present,due to the increase of coal mining intensity and depth,the shallow coal resources are decreasing day by day.Deep mining has become an inevitable trend of future coal mining in my country.However,compared with the shallow coal-rock mass,the structure,behavior characteristics and engineering response of the deep coal-rock mass are in the complex mechanical environment of "three highs and one disturbance",which makes the mechanical properties of the deep coal-rock mass fundamentally affected.sexual changes.Therefore,the control of surrounding rock in deep roadway has become a recognized technical problem in mining engineering circles at home and abroad.The surrounding rock stress is the superposition of deviatoric stress and spherical stress.The deviatoric stress controls the shape deformation of the rock unit,and the spherical stress controls the volume deformation of the rock unit.The deviatoric stress causes the plastic failure and deformation of the coal-rock mass,while the spherical stress causes the recoverable elastic deformation of the coal-rock mass.Among them,the deviatoric stress comprehensively considers the interaction of the maximum principal stress,the intermediate principal stress and the minimum principal stress,reflects the stress state of the coal and rock mass under the combined stress,and can better reveal the essence of the deformation and failure of the coal and rock mass.In view of this,this paper takes the roadway 33092 of Zhaozhuang Coal Mine as the engineering research background,and uses various research methods such as field measurement,theoretical analysis,numerical simulation,etc.,to conduct in-depth research on the stress field and failure law of the surrounding rock in the deep roadway under the state of three-dimensional stress.,to explore the temporal and spatial evolution law of the deviatoric stress field and plastic zone of the surrounding rock in the deep roadway.The specific work is as follows:(1)Through the on-site investigation,the specific situation of the surrounding rock damage of the roadway was obtained,which was manifested as asymmetric damage such as roof subsidence,coal wall gang,floor bottom drum,and anchor cable breakage.Based on the measurement of the loose circle and the results of borehole peeping,it is concluded that the loose circle of the 33092 road in Zhaozhuang Coal Mine is a medium-sized loose circle.(2)The deviatoric stress derivation formula of the coal-rock mass unit of the surrounding rock of the roadway is obtained through the elastic-plastic correlation theory,and by controlling the single-variable influencing factors,the roadway buried depth,lateral pressure coefficient and stress Lode angle under different conditions are analyzed.The influence on the distribution law of the deviatoric stress field of the surrounding rock of the roadway;the boundary equation of the plastic zone of the surrounding rock of the roadway is obtained by solving the maximum shear stress intensity criterion,and the buried depth of the roadway,lateral pressure coefficient,internal friction angle,cohesion,Influence of surrounding rock stress field direction on failure characteristics of surrounding rock plastic zone of roadway.(3)A three-dimensional numerical model was established by using FLAC3 D software.By simulating the excavation period of the 33092 roadway,the mining period of the 3309 working face and the mining period of the 3310 working face,the deviatoric stress field and the timespace evolution law of the plastic zone of the 33092 roadway in the whole life cycle were obtained.The research shows that: during the excavation of 33092 roadway and when it is not affected by the mining face,the deviatoric stress and plastic zone have symmetrical butterfly distribution;When deflection occurs,it shows asymmetric distribution of failure characteristics,and when affected by the secondary mining of the 3310 working face,the deviatoric stress field and plastic zone of the surrounding rock of the roadway develop to the deep.(4)According to numerical simulation and theoretical research,the improvement scheme of asymmetric support for 33092 roadway is proposed,and the improved support scheme and the roadway surrounding rock support stress field of the original support scheme are analyzed through numerical simulation,and the improvement is obtained.The latter support scheme has obvious advantages.Finally,the scheme was industrially tested in Zhaozhuang Coal Mine,and the on-site monitoring results showed that the asymmetric support improvement scheme effectively controlled the deformation of the surrounding rock of the roadway,and satisfied the safe and efficient use of the roadway during the service period.