主动式测压的瓦斯流动机理及压力演化规律研究

At present, active measuring gas pressure was used at large in coal mine. When the bore being used to measure gas pressure is sealed, there are some loss of gas in the coal that is located in the bore's entourage; after supplying air, the supplied high pressure air and the high pressure gas who is apart from the bore both flow to the zone where the gas pressure is lower; to the active measuring gas pressure, the flowing mechanism and evolvement rule of pressure distribution about them is basic theory problem that should be solved immediately. In the item, the research method includes theory analysis, numerical simulation, experiment in lab and application in locale; at first, the fluxion model of gas was decided in the condition of active measuring gas pressure. firstly, and on the basis of it, the gas flowing mechanism was analyzed, and the balance differential eguation of gas flowing was built; according to the calculation in theory or by simulation, the evolvement rule of pressure distribution in the surrounding of bore wall and the relation between it and some factors were obtained, and these factors include the supplement air pressure, the original gas pressure, the time of measuring gas pressure, the time of boring and sealing and physics mechanics character of coal; finally, the theory analytical production was used to coached the try of measuring gas pressure, and according to the result of test, the theory analytical production was validated and revised.

目前，主动式瓦斯压力测定法被煤炭企业普遍采用。测压钻孔被密封时，在钻孔周围一定范围内，煤体已经释放了部分瓦斯；主动补气后，补充的高压气体和远离钻孔的高压瓦斯都会向钻孔周围低压瓦斯带流动；这两股气流的流动机理及压力分布状况演化规律是主动式测压中亟待解决的基础理论问题。本项目采用理论分析、数值模拟、实验室实验及现场应用验证等方法，首先，建立主动式测压条件下的瓦斯流动模型，在此基础上，分析瓦斯流动机理，构建瓦斯流动平衡微分方程；通过理论求解或数值计算，得出测压钻孔周围瓦斯压力分布状况的演化规律及其与补气压力、原始瓦斯压力、瓦斯压力测定时间、打钻封孔时间及煤体物理力学性质等因素之间的关系；最后，利用理论研究成果指导现场测压试验工作，再根据试验结果，对上述研究成果进行验证和修正。

主动式测压在我国煤矿井下得到广泛应用，但是，与其相关的一些基础理论亟待补充与完善。本项目主要围绕主动式测压条件下的补气量、测定时间、应力集中对瓦斯压力的影响和测压钻孔周围煤层瓦斯压力演化规律开展研究；通过本项目的研究，得出了主动式煤层瓦斯压力测定补气量的理论计算公式、瓦斯压力测定所需时间的计算公式、不同测压条件下（不同测压时间、不同补气压力和不同原始煤层瓦斯压力）的煤层钻孔周围瓦斯压力分布状况、测压钻孔初始瓦斯压力计算公式、采掘应力影响下的煤层瓦斯压力计算方程组和非吸附平衡条件下测压钻孔周围瓦斯压力计算公式；并归纳总结出了以下规律，测压钻孔初始气体压力演化规律、主动式测压钻孔周围煤层瓦斯压力演化规律、采掘工作面前方瓦斯压力动态分布规律、非吸附平衡条件下测压钻孔周围瓦斯压力分布规律和几种重要因素影响补气量和测压时间的一般性规律；最后，应用上述理论研究成果对煤矿井下的瓦斯压力测定工作和煤与瓦斯突出防治工作进行了指导与结果验证。本项目研究成果的应用，有助于提高煤层瓦斯压力测定结果的可靠性与测定工作的经济性，也有助于提高煤与瓦斯突出预测的可靠性，可为矿井瓦斯防治工作提供有效的技术支持。