单裂隙结构特征对煤岩体内瓦斯流动特性的影响  

The influence of single fracture structure characteristics on the gas flow properties in coal-rock mass

作　　者：任建业 李雨成 张欢 马莲 张子翔 胡纪年 REN Jianye;LI Yucheng;ZHANG Huan;MA Lian;ZHANG Zixiang;HU Jinian(School of Safety and Emergency Management Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Shanxi Coal IMP and EXP Group Co Ltd,Taiyuan,Shanxi 030006,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]山西煤炭进出口集团有限公司,山西太原030006

出　　处：《采矿与安全工程学报》2023年第3期633-642,共10页Journal of Mining & Safety Engineering

基　　金：国家自然科学基金项目(52004170);山西省高等学校科技创新项目(2020L0109)。

摘　　要：为探究单裂隙粗糙度、开度等结构特征对煤岩体内瓦斯流动特性的影响,基于Weierstrass-Mandelbort分形函数生成不同粗糙度的裂隙轮廓曲线,构建含不同分形维数和裂隙开度的二维裂隙煤岩体模型。运用Fluent软件模拟分析裂隙分形维数、开度对裂隙内部及周边煤岩基质内瓦斯流动特性的影响,建立了可定量刻画裂隙结构特征对煤岩体相对渗流能力具有影响的流量系数双参数模型。结果表明:随着裂隙分形维数减小,裂隙开度增大,煤岩体渗流能力逐渐增强,且裂隙导流能力在煤岩体渗流过程中逐渐占优,流量占比最高达81%。随着分形维数增大,裂隙内瓦斯流动非线性强度系数呈指数型增大,影响裂隙内瓦斯流动非线性强度系数的主控因素逐渐由裂隙开度转变为分形维数,同时在煤岩基质靠近裂隙轮廓曲线离散程度较大的位置处,存在局部渗流速度增大的现象。当裂隙开度增大至1.5 mm后,裂隙分形维数对流量系数的影响起主导作用,反之,裂隙开度起主导作用。提出了流量系数与分形维数、裂隙开度的经验关系式。In order to investigate the influence of single fracture structure features such as roughness and openness on the gas flow characteristics within the coal-rock mass,a two-dimensional fractured coal-rock mass model with different fractal dimensions and fracture openness was constructed by generating fracture profile curves with different roughness based on the Weierstrass-Mandelbort fractal function.Fluent simulations were carried out to analyze the effects of fractal dimension and openness on the gas flow characteristics within the fracture and the surrounding coal matrix.A two-parameter model of the flow coefficient was established to quantitatively characterize the effect of fracture structure on the relative seepage capacity of the coal-rock mass.The results show that as the fractal dimension decreases and the fissure width increases,the seepage capacity of the coal-rock mass gradually increases,and the fissure inflow capacity gradually dominates the seepage process of the coal-rock mass,with the highest flow rate reaching 81%.As the fractal dimension increases,the non-linear intensity coefficient of gas flow within the fissure increases exponentially,and the main controlling factor affecting the non-linear intensity coefficient of gas flow within the fissure changes gradually from the fissure width to the fractal dimension,while the local seepage velocity increased in the coal matrix near the location where the fracture profile is more discrete.When the fractal dimension increases to 1.5 mm,the fractal dimension plays a dominant role in the flow coefficient.Conversely,the fracture width plays a dominant role,and the empirical relationship between the flow coefficient and the fractal dimension and the fracture width was proposed.

关 键 词：单裂隙 煤岩体 几何特征 分形维数 流动特性 

分 类 号：TD353[矿业工程—矿井建设]