Study On Phenomenon Of Underground Pressure In Top Coal Caving Of Large Inclined Angle In Trend And Tendency

With the increase of mining intensity and duration of the occurrence of coal reserves in good condition gradually reduce or even exhausted, block segment left, pillar and other reserves, a large dip more complicated geological conditions. In this paper, a comprehensive application of theoretical analysis, critical layer theory analysis, numerical simulation and other methods FLAC3 D for Taisha bilateral dip angle mining 92716 false inclined mining for actual geological conditions, Face overlying rock structure, the movement of overlying rock, roof control technology We were analyzed and discussed research results for the two-way high inclined seam mining safety to provide theoretical and practical basis. The study concluded that:(1) According to the 92716 working surface overburden specific circumstances, the use of key strata theory, determine the thickness of 12.2m of the old roof is critical layer, caving working face with a height of 10-14 m, with a height of 38-49 m fracture bending subsidence zone is 344m; the work surface with the Ministry of caving and fractured height compared with the lower part of a large development.(2) through Face mining process simulation 92716 Overburden Failure field evolution, beginning to end of the entire mining process, overlying strata and mining face plate with plastic damage than those occurring on a large coal damage zone mostly distributed in large coal overburden, big coal seam floor damage occurred only locally, 380 m before mining, large coal directly above the top height of 6.2m thick medium-grained sandstone has not been subjected to shear and tensile failure, mined to 380 m it is connected to the nearby shear plastic zones, thereafter until the end of the large coal mining area of overburden rock damage extended into the more stable state. Overburden Failure by the evolution of stars, the big mining to 40 m at the coal face, the key layer shear rupture, which is the old top of the first cycle to the pressure, with the front of the first chapter through the material mechanics method First get overlying sandstone strata caving step distance 32.2m consistent; when large coal mining face to 40 m ~ when 80 m, with the working face progresses, the shear breaking the region is increasing, we can see the mine to When 80 m, above the critical layer formation occurred in the past of shear failure; overburden rock damage region continues to expand, large coal mining 170 m, overburden rock damage zone extends to the second layer siltstone key layer overlying rock at the top of a large coal thick, big coal destroy field with the faceforward toward expanding along until the end of mining.(3) Face periodic weighting step away from stable, average weighting step distance of 14.2m, to step away from the pressure range of 13.9m-16 m, for the first time to pressure from the opening cut in the average 36.3m, cycle compressive strength is relatively small The average dynamic load coefficient was 1.12, indicating that mining method Caving Mining and not because of an increase in mining height is proportional to the bracket so that the load increases. Face Found discovery by an oblique direction different weighting step, first to the pressure on the work surface portion, gradually shift downward the face, and finally reaches the lower Face. Consistent with the theoretical analysis.(4) determine the selection by theoretical calculations ZF3200 / 16 / 24 B hydraulic support for the mining face normal use of stents, ZFG3000 / 16/24-type bracket ends the transition hydraulic support, ZT12000 / 16/24 for the next lane slip holder; select MG170 / 410-WD chainless haulage shearer; before and after the selection SGZ-630/264 type flexible scraper conveyor. Support load unevenly distributed. During stent load observation, we found most of the holder of the front pillar working resistance Face smaller than the rear pillar working resistance, through measurements and theoretical analysis, resulting in a pillar of support load is not the same before and after the main reasons: The Face Sloping- mining, Rear goaf caving gangue are applied to the face in the direction of the horizontal thrust, causing the rear bracket column carries a slightly greater than the pressure of the anterior column, according to the size and rules to step away from the pressure, improve the stent setting load, in order to change the past Coal wall rock stress state, reducing the end face of the roof subsidence, reduce spalling degree, strengthen surrounding rock control, to ensure that during the pressure face in security issues.