Study On Support Technology Of Transportation Roadway In 4322 Working Face Of Chengzhuang Coal Mine

In this paper,aiming at the support problem of transportation roadway in Chengzhuang Coal Mine,4322 working face is selected as the experimental object,and the strength and structure of roof rock mass of roadway are tested according to field test,theoretical analysis and numerical simulation.Based on the measured results,simulation research is carried out to analyze the breaking mechanism of bolt support and roadway surrounding rock under different stress and lithology environments.Similar to engineering experience,a low-density,high-strength and stable bolt support scheme for transport roadway in 4322 working face is finally put forward.While reducing the support density of bolt,the support strength of bolt in roadway is improved,and the deformation during roadway service is effectively controlled.Under the premise,the support cost is greatly reduced,the excavation efficiency is improved,and good application results are achieved.The main conclusions are as follows:(1)Sandstone is predominant in the area of 10 m above the roof of transport roadway in 4322 working face,with an average strength of 52.75 MPa and an average strength of 14.5 MPa for 3# coal body.The shallow coal body is relatively loose and its integrity is poor;the deep coal body is relatively complete,which is conducive to the active support of bolts.The transport roadway of 4322 working face belongs to medium stress field.The roof is sandstone.The damage scope and deformation degree of roadway are small.The damage scope of both sides and floor is larger than that of roof.It is necessary to strengthen the support of roadway side and roof when driving,so that the support density can be reduced appropriately.But the distance between rows should not be too large.The simulation of support density of transport roadway in 4322 working face shows that when bolt row spacing is 1100 mm,the distribution of stress,maximum displacement and plastic zone of roof and two sides are basically the same as that of row spacing of 1000 mm,which can reduce the density to a certain extent and improve the driving speed.(2)The initial design of bolt support in transport roadway of 4322 working face adopts resin lengthening anchorage,high pre-tightening force and high strength bolt support system,and reinforces the anchor cables.High strength and high pre-stress bolt support can overcome the main shortcomings existing in the application of ordinary high strength bolt,apply high pre-tension in time,effectively prevent discontinuous deformation of surrounding rock,and make the load of anchorage areauniform and uniform.Realize continuous transmission.The pre-tightening torque of bolt is not less than 400 Nm,the row spacing of roof bolt is 1100 mm,and there are 5bolts in each row,the spacing is 1150 mm.The row spacing of the upper bolts is 1100 mm,with 3 bolts in each row,and the spacing is 1200 mm.The roof anchor cables are arranged in 2-0-2 with a row spacing of 2200 mm,a spacing of 2000 mm and a pre-tightening force of 250 kN.With high strength adjustable center arch bracket and matching lock,the bearing capacity of bracket is not less than 500 kN.(3)Ground pressure monitoring of transport roadway support design in 4322 working face shows that: during excavation,surface displacement changes are small,bolt support effectively controls the stability of roof,and basically no separation occurs;during mining,under strong bolt support,the overall deformation of roadway is small,and the main reason for roof and floor closeness is roadway floor heave;the stress of bolt and bolt rope is relatively uniform,not too large.The working resistance of bolts and cables is 40%-50% of their breaking load,respectively.The supporting strength is safe and reliable.(4)In Chengzhuang Coal Mine,the driving footage of roadway is about 300meters/month when the original supporting scheme is used in one-time roadway construction.After adopting low-density support,the driving footage of roadway reaches 335 meters/month,and the driving footage of roadway is increased by 11.6%.Moreover,the research of this project can effectively save the amount of roadway supporting materials and reduce the environmental pollution caused by waste during the production of supporting materials.On the basis of guaranteeing the support strength of roadway,the support density of bolt is lowered as far as possible,the labor intensity of workers is reduced,the excavation efficiency of roadway is improved correspondingly,which is conducive to the quick connection of production of mine working face.It can provide experience data for roadway support under similar conditions in Chengzhuang Mine and other mines.It is not only practical,but also technically and theoretically strong,and has a clear application prospect.It has a good application value.