Research On Treatment Of Lower Protective Release Range And Release Gas At Close Distance Multiple Coal Seam

At engenerring background of Yue Liangtian Coal mine in Pan Jiangjing Coal co.,Ltd, adopted theoretical analysis, Flac3Dnumerial simulation and face ways, the paperanalyzes to exploit1318116lower protective seam site inspecting, upper overburdenseam tress, coal swelling and destruction, to discuss overburden released range. Onthe basis of backstopping period in face to analyze methane discharge volume andpredict them, the paper gives a controlling experiment on backstopping period face.The main contents and conclusions in this dissertation are as follows.Firstly, to analyze the forming of lower protective seam exploiting upperoverburden seam”three zones”, we get caving zone and fissure zone of overburdenafter1318116working face exploitation. We also get the situation of lower protectiveseam and overburden seam released distribution by the elastic-plastic mechanicstheory. We get the maxim release range of lower protective seam by the release rangetheory.Secondly, upper overburden seam produces release after lower protective faceexploited, and after it exploited forms three stress zones by coalseam trendingdirection—release zone, pressor area, stress restoration zone. By influence of tiltdirection coalseam on displacement, subsidence in return airway is larger than that inair intake. With the advance of working face, it forms different character zones, eg.caving zone, crack zone the bending zone. The middle of goaf produces largestretching and shearing destructing zone, and the exploited working face make thedistributiong of tilt directed plastic zone forming inclined ladder by tilt anglecoalseam. The damage of haul road is littlely larger than return airway. Stoppingexploited line of working face, open-off cut and airways was mainly damaged bystrenching and shearing.Thirdly, according to the numerical simulation of1318116working faceexploitation, we get data and calculate the maxim release range.Fourthly, protective layer were found through analysis of the working face of thegas emission factors, we use separate source method to get different unloading coalseam working face and gas emission.Fifthly, aiming at lower protective working face release gas, we propose fivemethods to make release gas treatment scheme, which are the wind hole gas predrainge, towards high roadway gas drainage, the roof return airway of prepumpingprotected gas, return airway relute gas drainage and return airway highe drilling gasdraingage. We get good result of release gas treatment by field test.