基于非吸附平衡的钻孔周围瓦斯压力分布规律

The distribution law of gas pressure around borehole based on non-adsorption equilibrium

传统钻孔周围瓦斯压力分布规律研究均以煤体对瓦斯的吸附处于平衡状态为基础,但是,瓦斯流动本身就会使得这种平衡被打破。本研究首先对瓦斯流动条件下的吸附平衡性实验方案进行了设计,并开展了相应的实验研究;在此基础上,对处于非吸附平衡条件下的钻孔周围瓦斯压力分布规律进行了研究,得出了钻孔周围煤层瓦斯压力计算表达式。研究结果表明,在瓦斯流动条件下,煤体对瓦斯的吸附作用处于非平衡状态,钻孔周围煤层瓦斯压力随时间基本呈线性规律下降。采用瓦斯压力指标对预抽煤层瓦斯消突效果进行检验,可能出现低指标突出现象,建议改用瓦斯含量指标。

Gas pressure is one of important parameters of the occurrence status of gas in coal seam, and thepre- cision of its value directly affects the safety production of coal mine. Traditional researches onthe law of gas pres- sure distribution around borehole are based on coal gas equilibrium absorption, but gas flow itself will break this equilibrium and cause an error between measured gas pressure and actual coal seam gas pressure. In the study, the experimental program of flowing gas tion equilibrium is improved and redesigned on the basis of similar simulation. The experiment revealed the gas flow rules in coal in the condition of nonequilibrium. Based on this result, the law of gas pressure distribution around borehole in the condition of non - absorption equilibrium is analyzed mathematically and a computation expression of gas pressure in coal seams around borehole is elicited. The study shows that, in the condition of gas flowing, the coal gas absorption is in a nonequilibrium state and gas pressure around borehole basically declines in linear rule with time. Using gas pressure indicators to check the gas bursts capacity index dispelling effect in gas pre -extraction coal seams may result in outburst with low index. The gas is, therefore, recommended to be used instead of the gas pressure index.