Study On Layout And Support Technology Of Roadway In Coal Pillar Face Of Shengping Coal Mine

It is important for improving the coal recovery rate and resource utilization ratio and prolonging the mine life to exploit protection coal pillar.When coal pillar is extracted,the stress concentration in the working face is large and the roadway maintenance is difficult.This paper systematically studied the bearing stress and distribution of plastic zone in the pillar under the influence of mining of two sides,the reasonable position of roadway and supporting tech nology,with Shengping Mine for research background,by using theoretical analysis,numerical simulation and field test.The main research achievements are as follows:(1)Established the models of isolated coal pillar and the inflection point of gob.(1)When the both sides of pillar is gob,the distribution of bearing stress near gob likes “Λ”.The concentration coefficient is 2.8,and the range of plastic zone affected by mining is about 0~40m;(2)At the inflection point of the gob,the support stress is fan-shaped.The stress concentration factor is about 2.3,and the plastic area range decreases to 35m;(2)Studied on stress distribution and deformation of roadway surrounding rock under different width of coal pillar in tunneling stage.Analyzed the rationality of the layout of the roadway in the stress reduction zone or the original rock stress zone and thus divided the scope of reasonable position of roadway: the width of the pillar near airway is 4m~6m,the width of the pillar near another roadway is 20m~40m;(3)During the mining stage,the pre stress of the working face and the support stress around the gob overlap with each other.Studied stress distribution of roadway surrounding rock under different width coal pillar during the mining process.And the reasonable location of the roadway was determined: the width of pillar near airway is 5m and the width of another pillar is 30m;(4)In view of the serious deformation of the surrounding rock in coal pillar mining,the bolt support technology with high pre-stress and high strength was put forward study.And studied the control mechanism of bolt density,found that when the spacing between the bolts is lower than 900 mm,the compressive stress field of the bolt will overlap with each other in the shallow part of the surrounding rock to form a compression arch.The asymmetric support technology is put forward and the reasonable supporting parameters of roadway are determined: The spacing between the bolts in pillar wall is 700 mm ×800mm,and the other one is 850 mm × 800 mm.Field industrial test results show that the research results effectively control the deformation of roadway surrounding rock and provide reference for the recovery of similar coal pillars.