Surrounding Rock Failure Mechanism and Differential Control Technology of Mining Roadway in Isolated Island Working Face
Aiming at the problem of surrounding rock stability control of mining roadway in isolated island working face,taking the track transportation roadway of S5-18 isolated island working face in Changcun Coal Mine as the engineering back-ground,the research methods of theoretical analysis,numerical simulation and field measurement are adopted.The distribution law of surrounding rock stress field of roadway in goaf lateral rail transportation roadway,the plastic zone shape and evolution law of roadway surrounding rock before and after mining in isolated island working face are obtained,and the failure character-istics of roadway surrounding rock are expounded.The mechanism of asymmetric expansion of plastic zone is revealed,and a re-gional differential control scheme is proposed based on the expansion characteristics of plastic zone of roadway surrounding rock.The results show that:the rail transport roadway is affected by the disturbance of lateral abutment pressure near the goaf,the partial stress in the surrounding rock is concentrated,and the asymmetric distribution in the plastic zone is obvious.Under the influence of mining,the sharp expansion range of the plastic zone of the rail transport roadway is about 25 m ahead of the working face,and the expansion range of the plastic zone of the roof,floor and coal pillar is obviously larger than that of the coal wall.The asymmetric expansion mechanism of plastic zone is obtained:the magnitude of partial stress expands the range of plastic zone,and the deflection of principal stress angle changes the expansion angle of plastic zone.The joint action of the magnitude of partial stress and the angle of principal stress results in an obvious asymmetric expansion of the plastic zone.Ac-cording to the distribution characteristics of the plastic zone of the surrounding rock of the roadway,the differential control scheme and specific parameters of the mining roadway in the isolated island working face are put forward,and the supporting effect analysis and industrial verification are carried out.The numerical simulation support effect analysis shows that the pres-sure bearing capacity of the surrounding rock of the roadway is enhanced and the plastic zone range is reduced;the deformation of the surrounding rock of the roadway in the engineering site is less than 250 mm,and the surrounding rock control effect is good,which ensures the safe and efficient mining of the isolated island working face.
isolated island working facemining roadwaysurrounding rock failuredifferential control
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