Study And Control Of Rational Layering Arrangement Of Roadway In Thick Coal Seam Mining Face

Coal is an indispensable material and foundation in the development of national economy and modern society.Before the 1990 s,the main way of coal mining in China was backward coal mining technology,with a recovery rate of less than 20%.It causes great waste and serious damage to coal resources.It is imperative to recycle coal resources in old mining areas efficiently.However,due to the existence of caving area in the caving area in the remining area,the layout and control of the roadway in the remining face are one of the key problems in the remining work.Based on the engineering background of no.3 coal seam in old mining of shanxi lingchuan chong an guanling mountain coal,as the engineering background,the stratification arrangement and control of the mining roadway of the no.3 thick coal seam in the old mining area were studied by means of field investigation and analysis,numerical simulation and other methods.The research contents and results are as follows:(1)The occurrence of no.3 coal seam in the old mining of guanlingshan can be roughly divided into four types: residual coal pillar,no caving top coal in the empty roadway,caving top coal in the empty roadway and its direct roof is complete,caving top coal in the empty roadway and partial roof mudstone caving;The lithology and physical and mechanical parameters of roof and floor rock strata are obtained by borehole observation and rock mechanics experiment.(2)By comparing and analyzing the surrounding rock conditions of roadway roof and floor under different layer layout,the support mode in the roadway,the treatment mode of the empty roadway,and the difficulty degree of the end and advance support,it is found that when the stoping roadway is tunneling along the coal seam floor,it is not only conducive to the equipment layout and stoping of the working face,but also more stable surrounding rock of the roadway.(3)Numerical simulation was used to study the stress distribution and plastic failure characteristics of heading along the top and bottom of the stopingroadway.The results show that from the working face to the range of 120 m behind the working face,the degree of plastic failure and the surrounding rock stress of the roadway increase gradually when driving along the top and bottom.From the working face to the range of 60 m in front of the working face,the plastic failure degree and the surrounding rock stress of the roadway gradually decrease when driving along the top and bottom.However,the plastic failure range of the stoping roadway along the bottom is smaller than that along the top,and the stress concentration is not obvious and the stress is small,which can meet the requirements of deformation control and safe use of the roadway surrounding rock.(4)Based on the analysis of the different conditions of surrounding rocks along the bottom of the stoping roadway,it can be concluded that: the roadway is arranged in the residual coal pillar,and the anchor wire +C30 flexible concrete wall is adopted to support the roadway,with the wall width of 800 mm;In the case of caving area in the empty area of the roadway,the anchor net cable+ i-steel shed + grouting +C30 flexible concrete wall is adopted to support,the spacing of the shed is 500 mm,and the width of the wall is 800 mm.