基于修正压汞法的不同瓦斯含量煤样孔隙结构及分形特征研究  

Study on pore structure and fractal characteristics of coal samples with different gas content based on modified MIP

作　　者：郭勇义 高亚斌 曹敬 张少奇 李子文 GUO Yongyi;GAO Yabin;CAO Jing;ZHANG Shaoqi;LI Ziwen(School of Safety and Emergency Management Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Graduate Education Innovation Center for Shanxi Coal Mine Safety,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学安全与应急管理工程学院,山西太原030024 [2]山西煤矿安全研究生教育创新中心,山西太原030024

出　　处：《中国矿业大学学报》2023年第6期1075-1083,共9页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(51804212,52004176);山西省基础研究计划资助项目(202203021211160);山西省研究生教育教学改革课题项目(2022YJJG039)。

摘　　要：近年来随着煤矿开采深度逐年增加,瓦斯灾害风险持续加剧.研究煤样孔隙结构特征,对矿井灾害防治具有重要意义.压汞法(MIP)是表征煤层孔隙结构的主要方法,但煤基质在高压下会出现显著的压缩现象,导致微、小孔难以得到准确描述.文章以山西省中北部矿井煤样为研究对象,提出一种规律校正法对MIP数据进行修正,结合分形分析,探讨了不同瓦斯含量煤样的孔隙结构及分形特征.研究结果表明:煤基质压缩系数Kc随着镜质组反射率R_(0,max)的增加呈现三段式变化规律,修正后的MIP数据能够更准确地描述煤体孔隙结构;高突煤样以半开放性微、小孔为主,提供了80.64%和81.23%的孔隙比表面积和体积,丰富的比表面积更易于瓦斯积聚;煤样中、大孔分形维数D_(1)和微、小孔分形维数D_(2)随着R_(0,max)的增大逐渐增加,且D_(1)明显小于D_(2),说明随着煤样的变质程度增加,孔隙整体发育逐渐复杂,表面更加粗糙,且微、小孔内部结构相对简单,孔隙表面较为光滑;高突煤样和低瓦斯煤样的平均D1和D2分别为2.26,2.76和2.09,2.55,高突煤样内部各阶段孔隙更加发育,非均质性更强.In recent years,with the increase of coal mining depth year by year and gas disasters have become increasingly prominent.Studying the pore structure characteristics of coal samples with different gas content is of great significance to mine disaster prevention and control.Mercury intrusion porosimetry(MIP)is the main method for characterizing the pore structure of coal seams,but under high pressure,the coal matrix will undergo significant compression,which makes it difficult to accurately describe micro and small pores.This paper takes coal samples from mines in northern central Shanxi Province as the research object,and discusses the pore structure characteristics of coal samples with different gas content based on modified MIP data and fractal analysis.The results show that the compressibility coefficient of coal matrix K_c shows obvious three-stage changes with the increase of the compressibility coefficient of coal matrix R_(0,max),and the modified MIP data can more accurately describe the pore structure of coal bodies.The high gas outburst coal samples are mainly semi-open micro and small pores,providing 80.64%and 81.23%of the pore specific surface area and volume,and the abundant specific surface area is easier for gas accumulation.Fractal dimensions of medium and large pores in coal samples D_1 and fractal dimensions of micro and small pores D_2 gradually increased with the increase of R_(0,max),and D_1 is significantly smaller than D_2,indicating that with the increase of the degree of metamorphism,the overall development of pores gradually become complex,the surface is rougher,and the internal structure of micro and small pores is relatively simple,and the pore surface is relatively smooth.The average D_1 and D_2 of the high outburst coal samples and the low gas coal samples are 2.26,2.76 and 2.09,2.55,respectively,indicating that the porosity in each stage of the high gas outburst coal samples is more developed,and the heterogeneity is stronger.

关 键 词：MIP修正 高突煤层 孔隙结构 分形特征 

分 类 号：TD713[矿业工程—矿井通风与安全]