Research On Mine Pressure Mechanism Of Gateway Of The Residual Coal Top-coal Caving

In rencent years, Shanxi province fully rectified and standardized mineral resources development order, and reorganized and intergrated many small coal mines, and changed slow and extensive production model formatted a long time ago, and built a number of high mechanization and large-scale production mines.But many integrated mine faced old mining residual coal area left by origin small coal that adopted low recovery old mining method, and recycling rate less than 30%, and a large number of coal resources were left, which could contain anthracite、coking coal and so on. That recovering these coal resources could promote the full development and rational utilization of resources and achieve resources efficient development and utilization demand, and could maintain coal industries long-term development.The paper based on secondary mining of Jinmei group Shenghua 3# coal seam 1301 working face old mining area, Shenghua old mining technical data and residual coal remining face early disclosureon the basis of thorough study,summed up the residual coal storage structure, application of the mine pressure monitoring, theory analysis and numerical simulation on the 1301 secondarymining working face of old mining the residual coal pillar failure law of surrounding rock in tunnel and its control technology research,the main research contents and conclusions are as follows:(1) Through the practical field monitoring, the plastic zone coal pillar in the entity coal is 6 m and the value is 10 m to 12.9m near the alley. The empty roadway make the roof-to-floor convergence, the two-sided displacement and the rate of change increase,which provides reasonable suggestions to advance roadway supporting.(2)By using similar simulation experiment and numerical simulation,it is concluded that when the working face and alley coal pillar achieve instability width the basic roof fracture in advanced alley a certain location, form the phenomenon the basic roof fracture in advance.(3) Under the circumstances the gateway basic roof fracture in advance,according to the single column and the gateway rock interaction relations, come to the conclusion that the advance single column rated working resistance is250 KN, the row spacing is 0.33 m.(4) Using the FLAC 3D numerical simulation software to simulate the working resistance changes of the gateway single column advanced in secondary mining face and entity coal working face of the first weighting. The results show that the single column can meet the support requirements when single column rated working resistance is 250 KN and the row spacing is 0.33 m.