Study On The Distribution Of Gas Content Of The Coal Body At The Laneway's Side Of Mechanized Excavation Face

Studying on the distribution of gas content of the coal body at the laneway's side of Mechanized excavation face, we can determine the width of gas emissions which can provide the parameters for forecasting the volume of the gas emissions in mine, testing of the gas content of the driving workings surface and forecasting index,this will play important practical significance on gas control of Mechanized excavation face.This paper makes the 4219 driving working surface in Chengzhuang Mine as the research object, adopting the method which combing theoretical analysis, numerical simulation and on-site testing. The specific method is as following:In the theoretical analysis aspect: after establishing the gas one-way flow percolation equation, we can transform the second order partial differential equation with variable coefficients into constant coefficients equation, and get the analytical solution. We can get that, only when the width of gas emissions zone is infinity, the gas pressure can reach the original coal gas pressure. While, when the width of gas emissions zone tends to a certain value, the gas pressure is very close to the original gas pressure.In the numerical simulation aspect: the one-way flowing of the gas of the coal body at the laneway's side is numerical simulated. And, we get the conclusion that the width of gas emissions zone growes with the original coal gas pressure, exposure time and permeability coefficient increasing. We ascert the largest width of gas emissions zone according to actual parameters at the experimental site.In the on-site testing aspect: drilling cuttings gas recorery index method and direct method are adopted to test the gas capacity at different depths of the laneway's side, gas capacity distribution rule of the coal body at the laneway's side of heading face is found out,and the width of gas emission zone is determined by SLogistic increasing function.This paper have concluded gas capacity distribution rule of the coal body at the laneway's side of the mechanized excavation face. gas content of deep coal is increasing continuously at vertical direction to the coal wall, and the extent of increasing is decreased continuously.Under the condition of unchanging original gas content,Along the direction of the tunneling roadway,gas content of the drift at the same depth first increases slowly,the closer to the head,the more significantly gas content increases.