The flowing and outburst mechanism of gas in coal-based pore and fractured medium
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摘要: 分析了瓦斯在煤基多孔介质中的运移条件;推导和讨论了瓦斯在煤基多孔介质中运移扩散的基本方程和影响因素;分析了煤与瓦斯突出产生的机理和渗透力学条件。提出瓦斯在煤基多孔介质中的运动是孕育煤与瓦斯突出的前提,而瓦斯压力梯度与浓度梯度的存在是驱动瓦斯在多孔介质中运动的内动力;煤与瓦斯突出的危险性主要取决于瓦斯压力梯度及其变化量的大小,而和瓦斯的绝对压力大小没有直接关系。煤与瓦斯突出的条件是由煤基多孔介质中瓦斯压力梯度的大小和煤体固体骨架的抗剪强度大小所决定。低渗透性的构造煤因对瓦斯运移阻力较大而容易形成瓦斯压力梯度的增加,从而更易于发生煤与瓦斯突出。Abstract: The paper analyzed the flowing conditions of gas in coal-based pore and fractured medium,discussed the basic movement equation of gas flow and diffusion in the pore and fractured medium as well as the main influence factors,analysed the coal and gas outburst mechanism and its dynamic conditions.It was recognized that gas flowing is the preliminary condition of coal and gas outburst,the gas pressure gradient is the basic force of coal and gas outburst.Coal and gas outburst was closely related to the gas pressure gradient instead of gas pressure.The coal and gas outburst conditions are mainly determined by gas pressure gradient and coal shear stress.It is easier to form coal and gas outburst in fractured coal due to its low permeability and high gas flowing resistance.
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Keywords:
- pore and fractured medium /
- gas flowing /
- pressure gradient /
- coal and gas outburst
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