Analysis On The Roof Sterss And Rock Deffoormaiton For Stirped Residual Mining Face Going Across Roadway

As the main energy sector, the coal plays a vital role in the development ofthe national economy. But our coal mining has always been the low recoveryrate and wasted. In the current our country coal resource demand is huge andgrowing conditions, it is imperative to improve the recovery rate of coalresources, extracting seam mining are is an important approach to improve thecoal recovery rate. For coal mining enterprises the residual coal mining canimprove economic efficiency, effectively solve the mine mining succeed,prolong the service life of aging mine.Actual situation, this paper tape residual coal occurrence by using elasticmechanics analysis, the three dimensional similarity simulation test andnumerical simulation, the method of combining the on tape residual coal miningare fundamental analysis and research.In view of the strip mining residual coal resources, in this paper, themechanical of coal pillar and roof and floor characteristics were analyzed.According to A.H. Wilson pillar theory, the stress of the coal pillar due todifferent role divided into edge yield zone and inner core. Roof stress is mainly borne by the nuclear area of coal pillar, edge of coal pillar due to stressconcentration under the action of pore fissure development. The roof above thecoal pillar is surrounded by triaxle stress, above because there is no support forthe old goaf roadway roof and it is easy to break and cave.On the basis of force analysis, with the geological conditions and the statusof the coal seam occurrence the residual coal occurrence conditions of ShanxiMeiYun Mining Group XiHe coal mine, we had a test with thethree-dimensional simulated experiment which is developed by TaiyuanUniversity and Technology themselves. Assuming that the actual situation, wedesigned different experiment of compound mining face: Room and pillar type,strip type and the mixture of two types. the experiment is designed into two-stepmining, The first step is initial simulation mining with room and pillar miningmethod, the second step in the old mining to simulate the residual coal miningafter a certain time. Roof stress and displacement of roof convergence andrelated experimental phenomena is observed and recorded in the process ofsimulation. This paper expounds on the strip type30°angle working facemining are starting cut process, inclined alley when the changing rule of thestress and displacement of roof and pillar deformation law, On the top of the oldfirst step distance and pressure and periodic weighting.On the basis of experimental simulation and engineering practice，the paperestablished a finite element model of the residual coal mining based on theresidual coal occurrence conditions of Shanxi MeiYun Mining Group XiHe coal mine, and simulate striped residual mining with the finite elemental program ofFortran. Through similarity simulation experiment study we have found that: Itwas that working face across the abandoned roadway has a great influence onthe coal pillar and the roof stress distribution. Working face across theabandoned roadway make the stress of the roof in front of working faceredistribution and the pillar stress state changes.