【作者】 任搴华；

【导师】 赵耀江；

【作者基本信息】 太原理工大学 ， 安全技术及工程， 2012， 硕士

【摘要】 随着浅部煤炭资源的持续开发,矿井开采强度不断增大,工作面瓦斯涌出超限己成为了制约煤矿安全生产的瓶颈。工作面瓦斯涌出的主要来源是采空区瓦斯涌出,所以要治理工作面瓦斯涌出超限就有必要先搞清楚瓦斯在采空区内的浓度分布和运移规律。瓦斯在采空区运移的主要驱动力是漏风,漏风又是采空区上隅角瓦斯浓度超限和遗煤自燃的直接原因。在停风和无其他驱动力下,瓦斯运移依靠采空区内的瓦斯涌出源项驱赶空气向压力边界上流动,形成渗流场,强度由瓦斯涌出源项强度而定,通常比较微弱,瓦斯涌出也十分缓慢,故本文不考虑在此驱动力情况下的瓦斯运移规律。本文主要研究没有瓦斯抽采(以U型通风为例)、仅有瓦斯尾巷排放即U+L型通风系统、高位钻孔组和瓦斯尾巷同时抽排所形成的三种风流场下的采空区漏风规律以及漏风作用下的瓦斯运移规律。本文首先分析了覆岩层结构,瓦斯涌出源和影响瓦斯涌出因素等瓦斯运移的外部环境,通过多孔介质基础理论系统总结了采空区瓦斯运移特征和采空区瓦斯流动基本规律。又以相似理论为基础探讨了建立相似模拟试验模型所要遵循的相似定理,相似条件和相似准则。本文用瓦斯流动理论和相似理论作为基础,以沙曲矿14025工作面实际尺寸为原型建立了相似模拟试验模型。以理论分析和试验研究相结合的方法,通过能位测定、示踪技术等手段分别对只有通风一种驱动力,只有瓦斯尾排放以及高位钻孔组和瓦斯尾巷同时抽排等多种驱动力下的情况进行相似模拟,根据在相似采空区模型内测得的风压和自燃三带划分的指标风速分析出风流在采空区内的源汇类型、流向以及指标风速距工作面距离变化的趋势,从而总结出漏风规律。通过对三种不同驱动力下瓦斯浓度的进行测定,用折线图绘出沿采空区走向和倾向瓦斯浓度趋势,总结出瓦斯浓度分布规律和运移规律,并且比较了同一通风系统增大压差以及不同通风系统增大压差对瓦斯浓度分布的影响。通过对比分析发现瓦斯浓度曲线随着三种不同驱动力变化有向采空区深部移动的趋势,高位钻孔组和瓦斯尾巷同时抽排对上隅角瓦斯的治理效果最好,但仍然有一定局限性。通过对三种不同驱动力下采空区漏风规律和瓦斯浓度分布及运移规律的研究为生产实际中采空区自燃三带和上隅角瓦斯治理提供了依据。更多还原

【Abstract】 With the continuous development of the shallow coal resources and mine mining strength increasing,, working face gas emission overrun has become the bottleneck; of restricting safety production in coal mine. The main source of gas emission from working face is goaf gas emission, so it is necessary to know concentration distribution and migration rule in the goaf before to manage working face gas emission overrun. The main driving force of gas migration in the goaf is air leak, which is the immediate reason for the upper corner gas concentration overrun in the goaf and the left coal self-igniting. Under the condition of blowing-out and no other driving force, gas migration is dependent on gas emission source term driving air to flow to the pressure boundary, forming percolation field, the intensity of which is decided by the intensity of gas emission source term, which is relatively feeble in general, and gas discharge is also completely slow, so this paper takes no account of the delivery law of methane under this circumstance of this driving force. This paper mainly studies on Air leakage law in the goaf and Gas migration rule under no gas extraction such as U ventilation system and tail roadway drainage gas and high position bores with tail roadway drainage gas.This paper first analyzes gas migration external environment including the structure of overlying strata and Gas emission source and influence factors of the gas emission, and systematically summarizes gas migration characteristics and the basic law of gas flow in the goaf by means of theory in porous media, and taking the similarity theory to analyze the simulation test model to flow similitude theorem and condition of similarity and similitude criterion.The paper with theory of gas flow and theory of similarity as a foundation established similar simulation test model which is based on the shaqu mine14025working face of actual size. The paper with method of theoretical analysis and experimental, makes analog simulation by means of pressure energy measuring and tracer technique under under no gas extraction such as U ventilation system and tail roadway drainage gas and high position bores with tail roadway drainage gas. In a similar model according to measuring wind pressure and wind speed, the paper analyses the source and sink types of air flow and flow direction and tendency of distance which is apart from working face, and sums up the air leakage rule. The paper summed up the gas concentration distribution and migration rule through measuring the gas concentration under three different driving force, drawing broken line graph for tendency of gas concentration along toward and along the tendency, Compared the influence of gas concentration distribution under the same ventilation system different pressure and different ventilation system and pressure.By comparison and analysis, the author finds that the gas concentration curve tends to migrate to deep goaf with the transformation of three different driving force, the harnessing effect on the upper corner gas is the best when high-order borehole group and gas tail roadway conduct pump drainage at the same time, however, this method is still having some limitations. Through studying the air leakage law of goaf, as well as the concentration distribution and the displacement and movement law of gas under three different driving force, so as to provide justification for gas control on spontaneous combustion "three zones" of the goaf and the upper corner in the production practice.更多还原