| In the process of coal mining under confined aquifer, when the height of waterflowing into fractured zone caused by exploiting develops to the bottom ofconfined aquifer, the fractures will get to the confined aquifer. Under the waterpressure, the water in confined aquifer flows into working area. This will resultin water bursting hazard. In addition, with the coal mining face advancing, theoriginal rock stress distribution changes inevitably. When the redistribution oforiginal rock stress exceeds the ultimate limit, this will result in breaking andcollapsing of coal rock bed. This phenomenon reflects itself in the way of the firstpressure and the periodic pressure. When the pressure is intense, it will result inbreak-off of support. The reason of water inrush and support break-off can beattributed to the generation and development of fractures and breaking andcollapsing of coal rock bed. Sometimes, the water inrush and the support break-offdo not occur at the same time. But against the specific geological background, theyhave a correlation in time and space. Researching the cause of the correlation has aimportant practical significance for the safety of coal mining, and can provide thetheoretical foundation for this kind of calamity at6130working face in Qi Dongcoal mine.In this paper, on the basis of collecting and analyzing data, it uses themeasured data and the theoretical analysis method. Taking the water inrush andsupport break-off calamity at6130working face for example, it makes use of thekey overburden layer theory to research the law of overlying strata of crack’sgeneration, development and breaking. And by using the software UDEC and theorthogonal test, it attempts to find out some important factors which affect thewater inrush and support break-off. This can provide a reference for the predictionof the water inrush and support break-off disaster caused by coal mining under theconfined aquifer. |
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