Gob-side roadway support in thick seam using flexible formwork concrete wall
As a kind of non-coal pillar mining technology,flexible formwork concrete wall for gob-side entry retaining has been applied in many coal mines in Shendong mining area of China.In order to solve the problem of poor stability,drastic deformation and difficult support of the surrounding rock during reuse of gob-side entry,taking the No.52606 gob-side entry retaining working face with flexible formwork concrete wall in Daliuta Coal Mine as the background,theoretical analysis,numerical simulation and on-site measurements were carried to study the surrounding rock deformation characteristics of the flexible formwork concrete wall gob-side roadway,set up surrounding rock mechanical model for gob-side roadway with the flexible concrete wall,and obtain the stress evolution law for the whole life cycle of the roadway from the tunneling stage to the reuse stage,thus to propose the corresponding support schemes according to different working stages of the roadway.The research results show that:the overlying strata force acts directly on the connecting part of immediate roof and concrete wall rock layer,which leads to the transfer of lateral abutment pressure,and larger deformation of the roadway surrounding rock.The advance abutment pressure of secondary mining produced roof plastic damage in the front of the retained roadway.The plastic damage is connected with floor plastic zone,which will intensify the destruction of sides of the coal wall.The on-site engineering practice shows that,supporting at specific time and zone along gob-side roadway can improve the stress environment and effectively control the deformation of surrounding rock.
flexible formwork concrete wallgob-side entry retainingroadway supportsurrounding rock controldeformation mechanism
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