【作者】 李兵；

【导师】 林柏泉；

【作者基本信息】 中国矿业大学 ， 安全工程（专业学位）， 2021， 硕士

【摘要】 瓦斯一直以来是困扰煤矿企业进行安全生产的重大危险源,我国许多矿井虽为低瓦斯,但开采时由于回采速度、通风方式等原因却出现高瓦斯涌出的现象,具体表现为上隅角瓦斯浓度频繁发生超限,这极大的危害了矿井的安全生产。内蒙古牙星矿在生产时也遇到了同样的低瓦斯异常涌出问题,故本文以牙星矿426综放工作面为研究对象,针对4#煤层采空区存在的低瓦斯异常涌出,从理论和实践的角度对牙星矿涌出规律进行探究,得到的主要研究成果如下:结合牙星煤矿基本概况,依据现场施工条件测定煤层瓦斯基本参数,得到4#煤层的瓦斯赋存指标。随着工作面推进采空区瓦斯逐渐释放出来,造成上隅角处瓦斯积聚,结合现场实测数据对采空区的瓦斯涌出规律进行分析,研究结果为文章后期制定采空区瓦斯防治措施提供了理论依据。自主搭建了采空区动态承压破碎煤岩体渗流实验平台,以牙星矿破碎烟煤为研究对象,开展了采空区破碎承压煤体的渗透特性演化试验,一方面提出适用于破碎煤岩体的压实—气体渗透实验方法,另一方面可得到破碎烟煤逐步压实变形过程中瓦斯渗流特性,并且基于实验结果,探求了采空区煤岩体渗透率的分布模型,这种新型渗透率模型的提出有助于下一步研究。结合散体力学理论、渗流理论及气体动力学理论,依据426工作面现场实际情况,建立采空区破碎煤岩体流固耦合模型,利用COMSOL软件分析了426综放面采空区内部的多场分布规律,并且得到采空区内部垮落煤岩体的渗透率分布呈现“O”型状形式,这为指导现场进行采空区瓦斯治理提供了理论指导。根据426工作面的煤层赋存以及现场条件,结合经济可行的原则,提出了牙星矿综放面采空区瓦斯综合治理技术,分析了不同预埋立管步距下的上隅角浓度分布情况,从中总结出预立孔埋管的步距为15m较为合理,并且在426综放工作面进行了初次试验,通过现场数据考察,发现上隅角处的瓦斯浓度极大的下降,表明立管群抽采技术可以较好的降低上隅角瓦斯浓度,下一步该技术方案也可在牙星矿其它地质条件的相似的4#煤层工作面采空区进行有效应用。本篇文章有图37幅,表14个,参考文献94篇。更多还原

【Abstract】 Gas has always been a major source of hazard that plagued coal mining companies’ safe production.Although many mines in my country have low gas levels,high gas gushes out due to mining speed and ventilation methods.It shows that the gas concentration in the upper corner frequently exceeds the limit,which greatly endangers the safe production of the mine.The Yaxing Mine in Inner Mongolia also encountered the same problem of abnormal low gas emission during production.Therefore,this article takes the Yaxing Mine 426 fully mechanized caving face as the research object,aiming at the low gas abnormal emission in the goaf area of the 4# coal seam.From the perspective of theory and practice,the law of gushing out of Yaxing Mine was explored,and the main research results obtained are as follows:Combined with the basic situation of Yaxing Coal Mine,the basic parameters of coal seam gas were measured according to the on-site construction conditions,the gas occurrence index of coal seam #4 was obtained.Equivalently as the working face advances,the gas in the goaf is gradually released,causing gas to accumulate in the upper corner.Combining the field measurement data to analyze the gas emission law in the goaf,the research results provide for the later development of the gas prevention and control measures in the goaf the theoretical basis.Independently set up a dynamic pressure-bearing broken coal and rock mass seepage experiment platform of the goaf.Taking the crushed bituminous coal in the Yaxing Mine as the research object,carried out the evolution test of the permeability characteristics of the broken pressurized coal in the goaf.On the one hand,rock mass compaction-gas permeation experiment method.On the other hand,the gas seepage characteristics during the gradual compaction and deformation of the broken bituminous coal can be obtained.Based on the experimental results,the permeability distribution model of coal and rock mass in the goaf is explored.This new type The permeability model is helpful for further research.Combining the theory of granular mechanics,seepage theory and gas dynamics theory,and based on the actual situation of 426 working face,the fluid-solid coupling model of broken coal and rock mass in the goaf is established,and COMSOL software is used to analyze the internal multiple the field distribution law,and the permeability distribution of the collapsed coal and rock mass inside the goaf is in the form of an "O" shape,which provides theoretical guidance for on-site gas control in the goaf.According to the coal seam occurrence and site conditions of the 426 working face,combined with the principle of economic feasibility,a comprehensive gas control technology for the goaf of the fully mechanized caving face of Yaxing Mine is proposed,and the upper corner concentration distribution under different embedded riser steps is analyzed.From it,it was concluded that the step distance of the pre-hole buried pipe is15 m is more reasonable,and the first test was carried out at the 426 fully mechanized caving face.Through field data investigation,it was found that the gas concentration at the upper corner was greatly reduced,indicating that Group extraction technology can better reduce the gas concentration in the upper corner.The next step is that the technical solution can also be effectively applied in the goaf of the 4# coal seam with similar geological conditions in the Yaxing Mine.This article has 37 pictures,14 tables,and 94 references.更多还原