Study On Resuse Mechanism And Technology Of Gob-side Entry Retaning In900m Deep Mine

Gob-side entry retaining is system engineering and its life cycle should beginwith the roadway excavation. According to the evolution of the roadway function, thewhole life cycle could be divided into three stages: Early Stage from roadwayexcavation to former mining face pass; Mid Stage from mining face pass to formermining face stoping over; Later Stage from roadway repairing to next mining facestoping over. Because of mining depth extension and particular advantages ofGob-side entry retaining, application of Gob-side entry retaining in deep mine ispromoting. As deep mine "5-high and2-disturbance" special mechanical mininggeological environment, the Gob-side entry retaining with composite roof and floor indeep mine badly damaged when next mining face stoping, surrounding rock wasextremely loose and broken, it was difficult for the real technology advantage ofGob-side entry retaining come true.Based on the gob-side entry retaining reparation engineering of first coal miningface in Zhuji mine around900m underground，this mining face has9.1m compositeroof and3.8m composite floor. Reuse mechanism and technology were studied bytheoretical analysis, numerical simulation and field measurement. Activitycharacteristics of overburden before retained roadway reuse was analyzed withtheoretical knowledge, structure characteristics of roadway surrounding rock wasconcluded, reuse feasibility was evaluated, reuse reasonable principle andconstruction process were determined; instability characteristics of surrounding rockwas researched by statistical analysis, the conception of“critical structure betweeninstability and stability” was proposed，reuse reasonable time was determined;Evolution law of surrounding rock stress was analyzed by numerical calculation andRFPA numerical simulation, initiative-passive collaborative supporting system wasconcluded; roadway reuse time was adjusted, reuse process was optimized androadway supporting parameters was corrected with the method of field practice andthe pressure observation.Research result was applied in the gob-side entry retaining reparationengineering in Zhuji mine successfully，results of ground pressure monitoring showedthat deformation of ribs was lower than90mm, relative deformation of roof and floorwas lower than200mm, there was not obvious separation in roof stratum, cable forcewas uniform and reasonable, repaired roadway deformation was controlled effectively. All indexes satisfied the requirements of the next mining face.