FLOOR ROADWAY STABILITY IN REPEATED MINING OF CLOSE DISTANCE COAL SEAMS IN LULING COAL MINE
MA Zhenqian1,JIANG Yaodong2,3,YAGN Yingming1,ZHANG Kexue1
(1. Faculty of Resources and Safety Engineering,China University of Mining and Technology,Beijing 100083,China;
2. School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing 100083,China;3. State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Beijing 100083,China)
Abstract:Taking II82 district in Luling coal mine as the engineering background,the dynamic evolution rule of floor stress,the stress characteristics and displacement distribution of the floor roadway were analyzed by similar material simulation test and numerical simulation. The results show that the floor stress distribution has obvious cyclical fluctuations. The fluctuation range in first mining is the greatest,and the degree of the concentration and unloading of the floor stress and the normal distance from coal seam showed a negative correlation relation. Considering the characteristics of developed rock fracture and large range of loose circle,this paper,based on double-layer bolting-mesh-shotcrete support and combined with grouting anchor bolt reinforcing and hollow grouting anchor cable reinforcing methods,proposed that mobilizing the bearing capacity of surrounding rock can make the support system and surrounding rock as a whole to bear. The field test shows that this support scheme can effectively control the stability of roadway,the roadway was stable after one month and the amount of floor heave is less than 100 mm.