1. College of Mining Engineering,Taiyuan University of Technology,Taiyuan　 030024,China;2. Key Laboratory of In-situ Property-improving Under Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan　 030024,China

利用自主研发的MCQ-Ⅱ型煤层瓦斯驱替试验装置,对原煤大尺寸（100 mm×100 mm×200 mm）试件,进行了恒定温压（25℃,31 MPa）条件下CO2在贫煤、贫瘦煤和弱黏煤3种煤阶煤中的注入储存试验,对CO2注入储存过程中煤体膨胀变形特性进行了测量分析;并对小尺寸（6 mm×6 mm×6 mm）原煤试件通过CT扫描,研究了3种煤样的微观结构特征。主要结果为:对最小观测尺度为4.5μm的CT重建图像,通过统计分析,发现贫煤孔隙率（4.67%）小于贫瘦煤孔隙率（5.39%）小于弱黏煤孔隙率（12.10%）;在31 MPa体积应力约束条件下,持续12 h的CO2注入过程中,煤体膨胀变形受孔隙压力与CO2吸附变形的共同作用,且体积膨胀百分比与CO2注入储存量呈线性关系;在注入储存相同量气态CO2条件下,贫煤体积膨胀应变大于弱黏煤大于贫瘦煤;由于煤体层理性结构特征,弹性模量在垂直与平行层理2个方向上的差异性,煤体在垂直层理方向膨胀应变大于平行层理方向应变,且2个方向膨胀应变均与CO2储存量呈线性关系。

In order to investigate the coal volumetric swelling during CO2 storage, the self-developed MCQ-ⅡCO2 -ECBM experimental equipment was used to perform coal deformation through injecting CO2 to meager coal,meager lean coal and weakly caking coal samples (100 mm × 100 mm × 200 mm) with constant injection pressure under 31 MPa bulk stress at 25 ℃ . At the same time, the micro-pores were investigated with nine small coal samples (6 mm×6 mm×6 mm) through a micro-CT system. The results show that:At minimum 4. 5 μm observation of CT sec-tion structure,the meager coal porosity (4. 67% ) is less than that of meager lean coal (5. 39% ) and weakly caking coal (12. 10% );During 12 hours of CO2 injection,coal volumetric strain is influenced by pore pressure and CO2 ad-sorption swelling,which is linearly proportional to the amount of gaseousness CO2 storage under 31 MPa confinement pressure;With the same CO2 storage,the volumetric swelling strain of the meager coal is more than that of the weakly caking coal and meager lean coal;Due to the anisotropy of modulus of elasticity,the radial strain increases faster than the axial strain and both of them are linearly proportional to the amount of gaseousness CO2 storage.

国家杰出青年基金资助项目(51225404)；“三晋学者”支持计划资助项目(2013)；

Zhang Beining,Liang Weiguo,Han Junjie,et al. Experiment on swelling strain of confined coal mass with CO2 sequestration[J]. Journal of China Coal Society,2016,41(2):324-331.