高瓦斯面顶板走向钻孔抽放数值模拟与试验

Numerical simulation and experimental study of methane drainage of goaf from drills along roof strike

高瓦斯矿井"U"型通风工作面采空区上隅角容易积聚瓦斯。以渗流理论为基础,根据气体扩散定律和质量守恒定律,建立了顶板走向钻孔抽放采空区瓦斯流场数学模型,并用6点隐式有限差分法进行了求解。以VB6.0为平台,利用工程软件SURFER模拟了抽放钻孔周围瓦斯压力场,并在现场进行了工业试验。理论研究与现场实践均表明:顶板走向钻孔抽放采空区瓦斯是解决高瓦斯工作面上隅角瓦斯积聚的一种行之有效的措施;顶板裂隙程度和状态是影响瓦斯抽放量的主要因素,将钻孔布置在适当的裂隙带中,瓦斯抽放浓度可达30%～90%,抽放负压可达50～55 kPa;数值模拟方法研究采空区瓦斯运移等工程实际问题是可行的。

Aiming at the problems of methane accumulation at upper comer angle in coal faces of U-type ventilation system, applying percolation theory, gas diffusion law and the law of mass conservation, the mathematical pattern of methane drainage from drills along roof strike was established. An analytical solution was presented by adopting explicit finite difference method. Based on Visual Basic6.0, the methane pressure field around drainage drills was obtained by SUFER software, and was also validated by the experiment on the spot. The simulation and experiment results show： （1） the method of methane drainage from drills along roof strike is effective to avoiding methane accumulation; （2） the degree and condition of roof crack are presented as the main factors affecting the drainage volume, and when the drills are disposed in cracking zone, gas drainage concentration and negative pressure can reach 30%-90% and 50-55 kPa respectively; （3） the numerical simulation provides an effective method in further studying of gas flow in goaf and can be taken as guidance in gas drainage and mine safety field.