Study On The Regularity Of Mine Pressure And The Behavior Of Overlying Rock Mass In Island Mining Face

In many mines in China,because of the geological structure division and the require for efficient production of mines,many mining areas exist a variety of forms of isolated island surface mining.The island face mining trigger the mining pressure,roadway support and roof management difficulties.These difficult problems are needed to be resolved urgently.In this paper,the s6-5 isolated island face of Changcun Coal Mine was studied by theoretical analysis,similarity simulation test and numerical simulation.The dynamic characteristics of overlying strata and the evolution law of stope during the mining of island face were studied,which provides some reference for the safe mining of coal pillars in Changcun Coal Mine.The main results are as follows:（1）Similar simulations were carried out by using the CM400/22 plane stress table.The three-dimensional static deformation measurement system was used to monitor the migration of the overlying strata excavated on the island face,and the overburden motion characteristics of the strata,the subsidence curve of the roof and the displacement vector of the overburden;（2）In the similar simulation experiment,the self-made strain brick was used to monitor the stress variation of the coal floor in the process of excavation.The stress curve of the bottom plate in the goaf area,the curve of the stress of the bottom face of the island face,the variation law of the surrounding rock in the process of excavation of the island face and the variation law of the floor stress were analyzed.（3）In order to analyze the law of the occurrence of strata pressure in the isolated island face,we used the FLAC^3D numerical simulation software to simulate the three cases in mining.The first case is the single section face.The second case is the mining working face under one side of the goaf.The last one is the mining working surface under the both sides the goaf.By using the numerical simulation software,the vertical stress distribution at the time of mining,the distribution law of the stress field of the surrounding rock,the evolution law of the plastic zone of the surrounding rock and the distribution law of the advance bearing pressure in the mining process were studied.