Study On The Layout Of Roadway And Supporting Technology For The First Mining Face Of 4^-2 Coal Seam Under The Extremely Close Goaf In Bailu Mine

The conditions of coal seam occurrence in China are complex and changeable.Under various conditions,it is an important problem and focus to explore and study suitable mining technology in order to prolong the production service life of mine and enhance the recovery rate of coal resources.In recent years,the coal resources of our country have been mined with great intensity,the reserves of coal resources with good occurrence state have decreased year by year,and some coal resources with poor occurrence conditions,such as the mining problems of close coal seam group,have gradually emerged.(1)The results show that the uniaxial compressive strength of 4-2 coal roof is34.13 MPa?the uniaxial tensile strength is 1.68 MPa,the Poisson's ratio is 0.19,the uniaxial compressive strength of 4-2 coal is 16.40 MPa,the Poisson's ratio is 0.31,and the uniaxial tensile strength is 0.73.(2)The plastic zone of surrounding rock is larger when the whole roadway is arranged by the external error method.At the same time,the plastic zone tends to increase further when it is close to the center line of the coal pillar floor.It is consistent with the plastic failure law of surrounding rock.Under the eight ways of arranging roadway,when the internal error method is used,the deformation of surrounding rock is obviously reduced compared with the external error method.Through calculation,it can be concluded that the position of the minimum unbalanced stress is 10 m?12 m from the edge of the pillar,so the final conclusion is that the mining roadway is arranged in the way of internal error of 10 m.(3)The reasonable spacing of anchor rod is 700 mm.by numerical simulation analysis In order to make the compressive stress zone formed by single row anchor rod make the surrounding rock form a large and uniform bearing body,the compressive stress zone formed by each single row anchor rod is superimposed and connected to each other so that the effective compressive stress zone between anchor rod and anchor rod is large.The supporting structure is effective as a whole.Finally,through calculation and analysis,it can be determined that the reasonable arrangement distance of anchor rod is 700 mm.There are 73 pictures,11 tables and 73 references in this paper.