“三软”煤层瓦斯参数变化特征及突出预警模型研究

发布时间：2018-02-08 16:42

本文关键词： 煤与瓦斯突出突出预警 “三软”煤层瓦斯参数预警模型综合权系数　出处：《河南理工大学》2014年博士论文　论文类型：学位论文

【摘要】：近几年来,我国重特大瓦斯事故不断发生,在国内外造成了极其恶劣的影响和巨大的经济损失。在我国的煤与瓦斯突出事故中,“三软”煤层中发生的突出占有一定的比重,尤其是在河南西部矿区“三软”煤层普遍存在。为了有效地预防和治理“三软”煤层煤与瓦斯突出事故,运用理论分析、软件拟合、实验室实验和现场观测等方法,对河南西部GC煤矿“三软”煤层瓦斯参数变化特征及突出预警模型进行了系统、深入研究,最后对“三软”煤层采煤工作面进行了煤与瓦斯突出预警实例分析和验证,得出了如下结果和结论:(1)根据Darcy定律、质量守恒定律和流体力学中微分形式的运动方程,建立了两个瓦斯流动的偏微分方程并联立求解,得出了煤层中径向不稳定流和球向不稳定流的瓦斯压力场方程,表明瓦斯压力p与时间t成反比,与半径r成正比;根据瓦斯压力场方程和达西定律推导出了半径为r的圆上单位面积瓦斯流量方程和煤层透气性系数λ的方程,这些参数都是关于时间t和距钻孔(或巷道)中心的距离r的函数。(2)利用理论分析和数值模拟对采煤工作面前方支承压力、煤层钻孔瓦斯涌出初速度、瓦斯涌出量、煤层透气性系数等瓦斯参数进行了分析研究,研究结果表明,这些参数具有相似的或相反的变化规律,是关于距煤壁距离x或者观测时间t的S型曲线和倒S型曲线的组合。煤层透气性系数、采煤工作面超前支承压力、煤层瓦斯压力关于距煤壁距离的曲线形式具有不很严格的对称性。结合“三软”煤层煤矿具体地质条件,可确定出煤层瓦斯参数变化规律,从而为矿井瓦斯灾害防治提供有效的理论指导。(3)构建了二维瓦斯流动方程和三维椭球体内部瓦斯流动方程,利用该方程解释了煤与瓦斯突出的过程。(4)对“三软”煤层煤与瓦斯突出的危险性进行了事故树分析,确定出了突出发生的概率,得出了突出发生的可能途径和预防突出的途径,最后确定出了导致突出的各因素的重要性排序。(5)构建了“三软”煤层煤与瓦斯突出预警的指标体系,该体系中包括煤层瓦斯压力、瓦斯放散初速度等8个指标;利用AHP方法确定出了各预警指标的权系数,基于事故树分析中基本事件的临界重要度,确定出了预警指标的权系数,将两者合成为综合权系数。(6)构建了基于可拓理论和综合权系数的可拓预警模型,并对GC煤矿“三软”煤层采煤工作面的突出危险性进行了预警分析,预警结果属于一般警度等级。
[Abstract]:In recent years, serious and serious gas accidents have occurred continuously in our country, which have caused extremely bad effects and huge economic losses at home and abroad. In the coal and gas outburst accidents in China, the outburst in the "three soft" coal seams occupies a certain proportion. In order to effectively prevent and control coal and gas outburst accidents in "three soft" coal seams, the methods of theoretical analysis, software fitting, laboratory experiments and field observation are used in order to effectively prevent and control coal and gas outburst accidents in the "three soft" coal seams in the western mining area of Henan Province. The variation characteristics of gas parameters and the early warning model of outburst in "three soft" coal seams in the western part of Henan Province are systematically studied. Finally, an example of coal and gas outburst early warning is analyzed and verified in the coal face of "three soft" coal seams. The following results and conclusions are obtained: (1) based on Darcy's law, mass conservation law and differential equations of motion in fluid mechanics, two partial differential equations of gas flow are established in parallel. The gas pressure field equations of radial unstable flow and spherical unstable flow in coal seam are obtained. It shows that gas pressure p is inversely proportional to time t and directly proportional to radius r; According to the gas pressure field equation and Darcy's law, the gas flow equation per unit area on the circle with radius r and the gas permeability coefficient 位 equation of coal seam are derived. These parameters are a function of time t and distance r from the center of borehole (or roadway). By using theoretical analysis and numerical simulation, the bearing pressure in front of coal mining face, the initial velocity of gas emission from coal seam borehole, and the amount of gas emission are obtained. The gas parameters such as permeability coefficient of coal seam are analyzed and studied. The results show that these parameters have similar or opposite variation laws. It is about the combination of S-type curve and inverted S-type curve of distance from coal wall x or observation time t. Coal seam permeability coefficient, advance supporting pressure of coal face, The curve form of coal seam gas pressure on the distance from coal wall has not very strict symmetry. Combined with the specific geological conditions of "three soft" coal seam coal mine, the variation law of coal seam gas parameters can be determined. Thus, the two-dimensional gas flow equation and the three-dimensional ellipsoid gas flow equation are constructed for the effective theoretical guidance for the prevention and control of mine gas disaster. Using the equation to explain the process of coal and gas outburst, the risk of coal and gas outburst in "three soft" coal seams is analyzed by accident tree analysis, the probability of outburst is determined, and the possible ways of outburst and the ways to prevent outburst are obtained. Finally, the importance order of the factors leading to outburst is determined. (5) the index system of early warning of coal and gas outburst in "three soft" coal seams is constructed, which includes 8 indexes, such as coal seam gas pressure, initial velocity of gas release, etc. The weight coefficient of each early warning index is determined by using AHP method. Based on the critical importance of the basic event in the accident tree analysis, the weight coefficient of the early warning index is determined. The extension early-warning model based on extension theory and comprehensive weight coefficient is constructed, and the outburst risk of "three soft" coal mining face in GC coal mine is analyzed. Early warning results belong to the general alert grade.
【学位授予单位】：河南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD713

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