| In the process of coal excavation,the mining gradually tends to the deep environment,the general stress increases,the rock structure and joint fissures develop obviously,which brings great challenges to the stability of the roadway and the surrounding rock control.In this paper,for the Zhaozhuang Coal Industry of Shanxi Coal Group,when it is preparing to mine the E1305 working face,the E13065 lane of the upper section due to the planned reuse will collapse and fall due to the fracture of the coal body,which will seriously damage the problem.It is proposed to use small coal pillar protection roadway in the new excavation roadway on the solid coal side of E13065 lane,considering the characteristics of coal body fracture,applying theoretical analysis,numerical simulation and field measurement research method,and carrying out the technology of small coal pillar driving roadway in the airspace area.Systematic research,analysis to obtain a reasonable coal pillar width and support program,and guide the implementation of the mining side.The main achievements are as follows:(1)The site complies with the secondary mining disturbance in the airspace area,establishes the overburden structure model of the airspace area,studies the fall law of the overburden strata in the open space under the condition of broken coal body,and analyzes the vertical pressure distribution of the overlying strata.Characteristics and bearing capacity of small coal pillars,preliminary theoretical calculations to determine the reasonable width range of small coal pillars.(2)Through the finite difference software FLAC3 D to simulate the variation of stress,displacement and plastic zone of surrounding rock during roadway excavation and mining under different width coal pillars,the simulation results are analyzed by visual data to obtain different coal pillar widths and different periods.The contour and cloud maps of the stress field and displacement field of the surrounding rock determined that the reasonable small coal pillar width is 12 m.(3)Analyze the variation law and control principle of surrounding rock of roadway under the condition of broken coal body,analyze the action mechanism of support body and surrounding rock,and propose to use anchor cable net W steel belt joint support to control roadway in tunneling and working face Deformation of surrounding rock during mining.Through the theoretical calculation of the approximate range of bolting cable support parameters for the roof and the two gangs,five kinds of support comparison schemes are proposed.The FLAC3 D numerical simulation of the stress,displacement and plastic zone evolution of the surrounding rock under the five supporting parameters during the excavation and mining of the E1305 working face is carried out.The comparative analysis shows that the optimal plan 4: five full-length anchor bolts for the gang,three Long anchoring anchor cable;five long anchor bolts for roof support.(4)12m coal pillar and support scheme 4: five full-length anchor bolts for the gang,three long anchor bolts;five long anchor bolts for roof support.The project is implemented in the E1305 working face.According to the roadway deformation during the roadway excavation and the mining face during the mining period,the actual measurement and analysis of the roadway support design and the validity of the surrounding rock control are ensured.Stability of roadway surrounding rock and safety of production.Through systematic research and analysis,the designed 12 m coal pillar width and roadway support parameters were successfully applied to the engineering implementation of the E1305 working face.The stability of the surrounding rock of the roadway is well controlled,and the recovery rate of the coal seam is improved,which has important economic significance. |
