高瓦斯矿井采煤工作面瓦斯地质分级评价方法与实践

瓦斯灾害是制约我国煤矿安全生产的主要灾害类型,在当前煤炭精准开采背景下,如何在工作面尺度实现瓦斯地质分级评价与风险精准识别,成为保障高瓦斯矿井安全、高效生产的关键。韩城矿区位于鄂尔多斯盆地东南缘渭北石炭—二叠纪煤田,构造条件复杂,瓦斯含量高且瓦斯动力现象频发,但工作面尺度瓦斯地质及致灾风险缺乏精细研究,对实际生产指导性不足。基于此,本文立足韩城矿区瓦斯地质条件,基于适用性与可行性原则优选煤层埋深、厚度、煤体结构、构造变形、绝对瓦斯涌出量和相对瓦斯涌出量共6个参数作为基本指标,厘定其分级评价阈值标准;基于多层次模糊数学评价原理,提出了包括评价参数体系确立与分级、隶属函数与权重确定、数学模型构建、地质成图与分区评价等流程的工作面瓦斯地质分级评价方法。在此基础上,以桑树坪矿4321回采工作面为例,对其进行网格剖分,耦合单因素地质指标计算瓦斯地质分级评价指数,结果显示该工作面瓦斯地质条件差异显著,可划分为Ⅰ型有利区、Ⅱ型相对有利区、Ⅲ型相对不利区和Ⅳ型不利区,分区结果与实际地质条件具有较好的一致性,煤层构造变形及煤体结构破碎是制约工作面安全回采的主要地质因素。建立的工作面多层次模糊数学瓦斯地质分级评价方法符合当前煤炭精准、安全开采的现实需求,对其他高瓦斯矿井和构造煤区瓦斯地质保障具有借鉴意义。

Method and practice of gas geological grading evaluation on coal mining face of high gas mine

Gas hazard is a main disaster type that restricts the safe production of coal mines in China.Under the current background of precise coal mining,the effective gas geological classification and accurate risk identification at the working face scale have become the key to ensure the safe and efficient production of high gas mines.The Hancheng mining area is located in the eastern Weibei Carboniferous Permian (C-P) coalfield in the southeastern margin of the Ordos Basin,and is characterized by complex tectonic conditions,high gas content and frequent gas dynamics phenomenon.However,the detailed study on gas geology law at working face scale is relatively limited,which is insufficient in guiding coal mining.Based on the gas geological conditions in the Hancheng mining area and the principles of applicability and feasibility,six parameters including coal seam depth,thickness,coal body structure,structural deformation and absolute/relative gas emission quantity are selected as basic indexes to determine the grading evaluation threshold criteria.Based on the principle of multi level fuzzy mathematics evaluation,a gas geological grading evaluation method for working face is proposed,which includes the establishment and grading of evaluation parameter system,the determination of membership function and weight,the construction of mathematical model,geological mapping and zoning evaluation.On this basis,taking the No.4321 working face in the Sangshuping mine as an example,the gas geological grading evaluation index is calculated by regional mesh generation and coupling single geological index.The results show the gas geological conditions of the working face vary significantly,which can be divided into four types:type I advantageous area,type II relatively advantageous area,type III relatively disadvantageous area,and type Ⅳ disadvantageous area.The grading and zoning results of the working face are in good agreement with the actual geological conditions.The structural deformation of coal seam and the resulted coal structure fragmentation are the main geological factors influencing the safe mining of working face.The multi level fuzzy mathematic gas geological grading evaluation method proposed in this paper meets the actual needs of current trend of accurate and safe coal mining,and has reference significance for the gas geological support in other high gas mines and tectonically deformed coal development areas.