| Reasonable support working resistance is an important guarantee of high efficiency of coal mine safety production. The caving mining of thick coal seam under14m theory and technology has become mature, but for hard rock intrusion directly with the top more than14m, under the condition of thick seam fully mechanized mining support working resistance of the theoretical analysis and study on the migration regularity of surrounding rock. Hill mine merger of coal seam3-5, on average,16.87m thick, large mining height are broken by a full mining thick. Due to the thick and immediate roof of coal seam with hard lamprophyre intrusive, appeared first on8102face of pillar crushed, dynamic pressure of roof and pillar mine pressure appear phenomenon such as abnormal. In this paper, in order to solve this problem, through the indoor experiment, field observations, theoretical analysis and numerical simulation method research to determine the lamprophyre intrusive, thick coal seam fully mechanized top-coal caving support working resistance of top directly. The concrete content includes:(1) Lamprophyre in water after the uniaxial compressive strength decreased obviously. Lamprophyre XRD diffraction experiments show that rock within the water to soften the chlorite and scanning electron microscopy (sem) experiments show that lamprophyre surface is the development of cracks and porosity.(2) through to the datong hill coal mine8102face to pressure situation, advance of support working resistance, law, damage analysis, concluded that hydraulic support working resistance rating of8102face is far from sharp to roof pressure, size and immediate roof of roof weighting in the presence of lamprophyre and lamprophyre in water softening has certain relations.(3) Through the direct roof presence of lamprophyre and lamprophyre in water softening after formation of the structure, calculated using the theoretical analysis, the direct roof no lamprophyre and lamprophyre in water softening after maximum working resistance of hydraulic support is13712.96kN·1, immediate roof lamprophyre in water softening of maximum working resistance of14555.8kN, frame1.(4) Use FLAC3D numerical simulation software has been the immediate roof of lamprophyre and lamprophyre in different support setting force after water softening subsidence is analyzed, the corresponding top-coal concluded when immediate roof no lamprophyre,12000kN hydraulic support setting force, the rack-1, the sink of top-coal to stabilise, then increase the supporting force of top-coal sinking at the beginning of the effect is not obvious; Also at the top of the direct lamprophyre support setting force of14000kN·1, top-coal subsidence stability; Immediate roof lamprophyre in water softening stent supporting force of12000kN, at the beginning of the rack-1, the sink of top-coal tends to be stable.According to8102working face of10000kN hydraulic support frame-1, can not meet the requirement of the production safety, on the basis of the above research, hydraulic support working resistance finally confirmed for15000kN, frame1. Subsequent several working face in the process of production no stent were killed appeared abnormal pressure, such as accident, that hill lamprophyre intrusive specially thick coal seam in coal mine fully mechanized selection of working resistance of15000kN·1hydraulic support is reasonable. |
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