| On both sides of the island working face are all goaf,so when the working face advances,it's surrounding rock changes are more serious,so will produce very big trouble about the working face of the safe and efficient mining,so thereasonably certain of the stop coal pillar has very important realistic meaning abot the safe and efficient mining.The paper is on the stop coal pillar of the leave size in jianxin coal mine of the Shan Xi province,carried out the mechanical parameters of the coal and rock and the analysis of component,start test of uniaxial load increase and decrease to discuss the law of change,he hysteresis is more and more big,there is a boundary between stresses,about is 60% of the maximum stress.The positive correlation between energy dissipation rate and stress.Carring out the elastoplastic theory about the stop coal pillar size of the 4206 island working face,it's stop coal pillar size at least is 120m;Using the UDEC to analysis single section and island surface,The stress concentration of island surface is about 1.8 that of single section,From the theoretical point,4206 length of stopped coal pillar is at least 120m;FLAC is used to simulate the pressure relief and no pressure relief,Through the analysis of the force and deformation of the gateway and the main roadway,it is concluded that the pressure relief is not necessary.The results show that the size of the coal pillar should not be less than 225 m when the pressure is not relieved;when the pressure is relieved,because the pressure effect is obvious,the size of the coal pillar should be about 150 m.According to the actual mining of the 4206 island working face,carring out the advanced roof breaking pressure relief,monitored the anchor rod(cable)is stressed,roadway surface changes,deep displacement of surrounding rock.In a word,It is reasonable to stop mining coal pillar size around 150 m in 4206 isolated island working face.This article has 62 figures,15 tables,and 92 references. |
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