基于分形理论的采空区遗煤孔隙率研究

Study on Porosity of Residual Coal in Goaf Based on Fractal Theory

自燃是煤矿的主要灾害,采空区自燃直接影响到回采工作面的生产,甚至能够造成严重的恶性事故。遗煤的存在是造成采空区自燃的根源,采空区内遗煤属于颗粒堆积型多孔介质范畴。由于遗煤颗粒形状相似但粒径大小差别巨大,具有分形特征。基于分形理论建立了采空区遗煤的粒径质量分布分形维数模型,并从实际的采空区内取煤样进行筛分对粒径分布特征进行了分析,通过分析计算得出六合煤矿和阜生煤矿的分形维数分别为2.2596和2.0554。分析影响煤自燃的孔隙主要是外部孔隙,对筛分出来的不同粒径的煤进行了外部孔隙率的测定,结合粒径分布的分形维数,对采空区遗煤的孔隙率进行了分析。通过研究粒径分布分形维数来分析采空区内的孔隙率分布,为采空区内孔隙率的研究提供了一个新思路。

Spontaneous combustion is the main disaster in coal mine.The spontaneous combustion in goaf directly affects the production of mining face,and even can cause serious accidents.The existence of residual coal is the source of spontaneous combustion in goaf.The residual coal in goaf belongs to the category of granular accumulation porous media.Because the shape of coal particles is similar in shape but large in size,they have fractal characteristics.Based on the fractal theory,the fractal dimension model of particle size and mass distribution of residual coal in goaf was established,and the characteristics of particle size distribution by sieving coal samples from actual goaf were analyzed.The fractal dimension of Liuhe coal mine and Fusheng coal mine were 2.2596 and 2.0554,respectively.The pores that affected coal spontaneous combustion were mainly external pores.External porosity of coal with different sizes was measured,combining with fractal dimension of particle size distribution,the porosity of residual coal in goaf was analyzed.By studying the fractal dimension of particle size distribution to analyze the porosity distribution in goaf,it provides a new idea for the study of porosity in goaf.