化石能源燃烧产生的CO₂导致全球气候变化，对人类赖以生存的环境造成了严重的伤害。但煤炭作为我国能源安全的压舱石，短期内无法直接去碳。采空区CO₂封存作为一项负排放技术，可以实现“碳中和”。然而，注入CO₂对采空区内遗煤的力学性质具有弱化作用，使得对采空区内的破碎煤岩体的压实特性产生了影响。本文以采空区CO₂封存技术为背景，研究了吸附CO₂对破碎煤岩体的压实和破碎特性的影响。采用实验方法，对比了吸附组和未吸附组的煤样在不同应力下的粒度分布、压实过程、破碎程度和分形特征。

根据不同粒径组质量百分数，获得了质量占比规律。基于Mandelbrot分形分布和威布尔分布，探讨了应力与分形维数D、破碎模量λ和破碎指数k之间的关系，获得了承压破碎后煤岩体的粒度分布规律。

对煤岩体的破碎特性进行了系统的研究。利用粒径级配曲线，定性地描述了煤岩体在不同承压条件下的破碎特征。利用相对破碎率和最大粒径绝对破碎率，定量地评价了煤岩体的破碎程度。通过对比吸附CO₂前后的破碎特性，分析了CO₂吸附对煤岩体破碎的影响机制。

基于初始粒径和新生粒径的质量分布，揭示了煤岩体在应力作用下的破碎动态特征，建立了粒径与破碎顺序和破碎程度的定量关系。利用分形理论，分析了分形维数、最大粒径绝对破碎率和相对破碎率之间的内在联系，提出了一种基于最大粒径绝对破碎率和分形维数的煤岩体破碎程度评价方法。

对破碎煤岩体在不同应力条件下的压实特性进行了系统的实验研究。利用应力应变曲线，揭示了破碎煤岩体的压实机理和阶段划分。利用切线模量、空隙率、碎胀系数等参数，量化了破碎煤岩体的压实程度和变形特征。同时，考虑了吸附CO₂对破碎煤岩体压实特性的影响，分析了吸附组与未吸附组之间的压实特征参数的差异，探讨了吸附CO₂对破碎煤岩体的微观结构和力学性能的作用机制，定性分析了采空区CO₂封存可能导致采空区发生再次沉降的机理以及演化过程。

The combustion of fossil fuels produces CO₂ that causes global climate change, which has caused serious damage to the environment that humans depend on for survival. However, coal, as the ballast stone of China’s energy security, cannot be decarbonized directly in the short term. CO₂ sequestration in mined-out areas, as a negative emission technology, can achieve “carbon neutrality”. However, the injection of CO₂ has a weakening effect on the mechanical properties of the residual coal in the mined-out area, which affects the compaction characteristics of the fractured coal-rock mass in the mined-out area. Based on the background of CO₂ sequestration technology in mined-out areas, this paper studies the effects of CO₂ adsorption on the compaction and fragmentation characteristics of fractured coal-rock mass. Using experimental methods, the particle size distribution, compaction process, fragmentation degree and fractal characteristics of coal samples in adsorption group and non-adsorption group under different stresses are compared. According to the mass percentage of different particle size groups, the mass proportion law is obtained. Based on Mandelbrot fractal distribution and Weibull distribution, the relationship between stress and fractal dimension D, fragmentation modulus λ and fragmentation index k is discussed, and the particle size distribution law of coal-rock mass after compression fragmentation is obtained. The fragmentation characteristics of coal-rock mass are systematically studied. Using particle size gradation curve, the fragmentation characteristics of coal-rock mass under different compression conditions are qualitatively described. Using relative fragmentation rate and maximum particle size absolute fragmentation rate, the fragmentation degree of coal-rock mass is quantitatively evaluated. By comparing the fragmentation characteristics before and after CO₂ adsorption, the influence mechanism of CO₂ adsorption on coal-rock mass fragmentation is analyzed. Based on the mass distribution of initial particle size and new particle size, the dynamic characteristics of coal-rock mass fragmentation under stress are revealed, and the quantitative relationship between particle size and fragmentation order and degree is established. Using fractal theory, the intrinsic connection between fractal dimension, maximum particle size absolute fragmentation rate and relative fragmentation rate is analyzed, and a method for evaluating the fragmentation degree of coal-rock mass based on maximum particle size absolute fragmentation rate and fractal dimension is proposed. The compaction characteristics of fractured coal-rock mass under different stress conditions are systematically studied experimentally. Using stress-strain curve, the compaction mechanism and stage division of fractured coal-rock mass are revealed. Using tangent modulus, porosity, swelling coefficient and other parameters, the compaction degree and deformation characteristics of fractured coal-rock mass are quantified. At the same time, considering the influence of CO₂ adsorption on the compaction characteristics of fractured coal-rock mass, the difference between adsorption group and non-adsorption group in compaction characteristic parameters is analyzed, and the mechanism of CO₂ adsorption on microstructure and mechanical properties of fractured coal-rock mass is discussed. The mechanism and evolution process of possible secondary subsidence caused by CO₂ sequestration in mined-out areas are qualitatively analyzed.

[1]刘海涛, 徐建中. 双碳目标下多主体碳排放协同治理行为研究[J]. 煤炭技术, 2022, 41(5): 243–245.

[2]孙林岩, 汪慕红. 全球CO2排放量与地表气温升高的因果性检验[J]. 西安交通大学学报, 1997, 31(2): 123–128.

[3]黄震, 谢晓敏, 张庭婷. “双碳”背景下我国中长期能源需求预测与转型路径研究[J]. 中国工程科学, 2022, 24(6): 8–18.

[4]李洪言, 张景谦, 陈健斌, 等. 2021年全球能源转型面临挑战——基于《bp世界能源统计年鉴(2022)》[J]. 天然气与石油, 2022, 40(6): 129–138.

[5]习近平. 继往开来,开启全球应对气候变化新征程——在气候雄心峰会上的讲话[J]. 中华人民共和国国务院公报, 2020(35): 7.

[6]习近平. 共同构建人与自然生命共同体——在“领导人气候峰会”上的讲话[J]. 中华人民共和国国务院公报, 2021(13): 7–9.

[7]习近平. 在第七十五届联合国大会一般性辩论上的讲话[J]. 中华人民共和国国务院公报, 2020(28): 5–7.

[8]王国法, 刘合, 王丹丹, 等. 新形势下我国能源高质量发展与能源安全[J]. 中国科学院院刊, 2023, 38(1): 23–37.

[9]庄贵阳, 窦晓铭, 魏鸣昕. 碳达峰碳中和的学理阐释与路径分析[J]. 兰州大学学报(社会科学版), 2022, 50(1): 57–68.

[10]张贤, 李凯, 马乔, 等. 碳中和目标下CCUS技术发展定位与展望[J]. 中国人口·资源与环境, 2021, 31(9): 29–33.

[11]WEI Y-M, KANG J-N, LIU L-C, et al. A proposed global layout of carbon capture and storage in line with a 2 ℃ climate target[J]. Nature Climate Change, 2021, 11(2): 112–118.

[12]苏现波, 赵伟仲, 王乾, 等. 煤层气井地联合抽采全过程低负碳减排关键技术研究进展[J]. 煤炭学报, 2023, 48(1): 335–356.

[13]REINER D M. Learning through a portfolio of carbon capture and storage demonstration projects[J]. Nature Energy, 2016, 1(1): 15011.

[14]YUAN J-H, LYON T P. Promoting global ccs rdd&d by stronger U.S.–China collaboration[J]. Renewable and Sustainable Energy Reviews, 2012, 16(9): 6746–6769.

[15]谢和平, 任世华, 谢亚辰, 等. 碳中和目标下煤炭行业发展机遇[J]. 煤炭学报, 2021, 46(7): 2197–2211.

[16]袁亮, 张通, 张庆贺, 等. 双碳目标下废弃矿井绿色低碳多能互补体系建设思考[J]. 煤炭学报, 2022, 47(6): 2131–2139.

[17]TAUZIÈDE C, POKRYSZKA Z, BARRIÈRE J-P. Risk assessment of surface emission of gas from abandoned coal mines in france and techniques of prevention[J]. Mining Technology, 2002, 111(3): 192–196.

[18]LI W, REN T, SU E, et al. Is the long-term sequestration of co 2 in and around deep, abandoned coal mines feasible?[J]. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2018, 232(1): 27–38.

[19]HOU X W, HUANG D G, LI H Z, et al. Research on the mechanism and capacity of CO2 stored in abandoned coal mine gob[J]. Applied Mechanics and Materials, 2014, 522–524: 196–200.

[20]RAY S, DEY K. Feasibility of CO2 sequestration as a closure option for underground coal mine[J]. Journal of The Institution of Engineers (India): Series D, 2018, 99(1): 57–62.

[21]LIU S, LIU T, ZHENG S, et al. Evaluation of carbon dioxide geological sequestration potential in coal mining area[J]. International Journal of Greenhouse Gas Control, 2023, 122: 103814.

[22]黄定国, 侯兴武, 吴玉敏. 煤矿废弃矿井采空区封存CO2的机理分析和能力评价[J]. 环境工程, 2014, 32(S1): 1076–1080.

[23]王双明, 申艳军, 孙强, 等. “双碳”目标下煤炭开采扰动空间CO2地下封存途径与技术难题探索[J]. 煤炭学报, 2022, 47(1): 45–60.

[24]WANG K, WANG G, REN T, et al. Methane and CO2 sorption hysteresis on coal: a critical review[J]. International Journal of Coal Geology, 2014, 132: 60–80.

[25]苏现波, 赵伟仲, 王乾, 等. 煤层气井地联合抽采全过程低负碳减排关键技术研究进展[J]. 煤炭学报, 2023, 48(1): 335–356.

[26]袁亮, 姜耀东, 王凯, 等. 我国关闭/废弃矿井资源精准开发利用的科学思考[J]. 煤炭学报, 2018, 43(1): 14–20.

[27]袁亮, 杨科. 再论废弃矿井利用面临的科学问题与对策[J]. 煤炭学报, 2021, 46(1): 16–24.

[28]HU S, LI Z, FENG G, et al. Changes on methane concentration after CO2 injection in a longwall gob: a case study[J]. Journal of Natural Gas Science and Engineering, 2016, 29: 550–558.

[29]荆蕊, 王雪峰, 乔玲, 等. 电厂烟气注入采空区防灭火技术的研究进展[J]. 煤炭工程, 2021, 53(11): 125–130.

[30]孙可明, 罗国年, 王传绳. 采空区注超临界CO2防灭火试验研究[J]. 中国安全生产科学技术, 2019, 15(5): 117–122.

[31]李文川. 高瓦斯矿井采空区注入CO2防治遗留煤体自燃研究[J]. 煤炭技术, 2023, 42(1): 166–170.

[32]FENG G, WU Y, ZHANG C, et al. Changes on the low-temperature oxidation characteristics of coal after CO2 adsorption: a case study[J]. Journal of Loss Prevention in the Process Industries, 2017, 49: 536–544.

[33]李宗翔, 刘宇, 王政, 等. 九道岭矿采空区注CO2防灭火技术数值模拟研究[J]. 煤炭科学技术, 2018, 46(9): 153–157.

[34]姜奎, 王怡, 任广意, 等. 姚桥煤矿8059工作面采空区注CO2防灭火技术参数优化模拟与应用研究[J]. 矿业安全与环保, 2021, 48(3): 74-78+84.

[35]王继仁, 张英, 郝朝瑜. 半“O”型冒落采空区注CO2防灭火的数值模拟[J]. 中国安全科学学报, 2015, 25(7): 48–54.

[36]高飞, 邓存宝, 王雪峰, 等. 烟气注入采空区封存的可行性与安全性分析[J]. 中国安全生产科学技术, 2016, 12(07): 60–64.

[37]KUMAR H. An overview of characterization and sorption capacity of coal for CO2 sequestration[J]. Arabian Journal of Geosciences, 2022, 15(15): 1364.

[38]翟光华, 段利江, 唐书恒, 等. 二氧化碳与煤作用机理的实验研究[J]. 煤炭学报, 2012, 37(5): 788–793.

[39]GUO X, WANG Z, ZHAO Y. A comprehensive model for the prediction of coal swelling induced by methane and carbon dioxide adsorption[J]. Journal of Natural Gas Science and Engineering, 2016, 36: 563–572.

[40]周动, 王辰, 冯增朝, 等. 煤吸附解吸甲烷细观结构变形试验研究[J]. 煤炭学报, 2016, 41(9): 2238–2245.

[41]WANG R, WANG Q, NIU Q, et al. CO2 adsorption and swelling of coal under constrained conditions and their stage-change relationship[J]. Journal of Natural Gas Science and Engineering, 2020, 76: 103205.

[42]张遵国, 陈毅, 唐朝, 等. 煤体CO2吸附/解吸变形特征及变形模型[J]. 煤炭学报, 2022, 47(8): 3128–3137.

[43]WALKER P L, VERMA S K, RIVERA-UTRILLA J, et al. A direct measurement of expansion in coals and macerais induced by carbon dioxide and methanol[J]. Fuel, 1988, 67(5): 719–726.

[44]祝捷, 张敏, 姜耀东, 等. 煤吸附解吸CO2变形特征的试验研究[J]. 煤炭学报, 2015, 40(05): 1081–1086.

[45]张倍宁, 梁卫国, 韩俊杰, 等. 应力约束下储存CO2煤层膨胀变形特性试验研究[J]. 煤炭学报, 2016, 41(02): 324–331.

[46]DAY S, FRY R, SAKUROVS R. Swelling of moist coal in carbon dioxide and methane[J]. International Journal of Coal Geology, 2011, 86(2–3): 197–203.

[47]刘延保, 曹树刚, 李勇, 等. 煤体吸附瓦斯膨胀变形效应的试验研究[J]. 岩石力学与工程学报, 2010, 29(12): 2484–2491.

[48]李祥春, 聂百胜, 何学秋, 等. 瓦斯吸附对煤体的影响分析[J]. 煤炭学报, 2011, 36(12): 2035–2038.

[49]陈结, 潘孝康, 姜德义, 等. 三轴应力下软煤和硬煤对不同气体的吸附变形特性[J]. 煤炭学报, 2018, 43(S1): 149–157.

[50]贺伟, 梁卫国, 张倍宁, 等. 不同煤阶煤体吸附储存CO2膨胀变形特性试验研究[J]. 煤炭学报, 2018, 43(5): 1408–1415.

[51]WU Y, LIU J, ELSWORTH D, et al. Evolution of coal permeability: contribution of heterogeneous swelling processes[J]. International Journal of Coal Geology, 2011, 88(2): 152–162.

[52]翟盛锐. 不同粒度型煤煤样瓦斯吸附-解吸变形特征实验研究[J]. 中国安全生产科学技术, 2018, 14(6): 84–89.

[53]何立国, 杨栋. 超临界CO2对煤体力学特性劣化影响研究[J]. 矿业研究与开发, 2021, 41(2): 94–99.

[54]高保彬, 吕蓬勃, 郭放. 不同瓦斯压力下煤岩力学性质及声发射特性研究[J]. 煤炭科学技术, 2018, 46(1): 112-119+149.

[55]XUE Y, RANJITH P G, CHEN Y, et al. Nonlinear mechanical characteristics and damage constitutive model of coal under CO2 adsorption during geological sequestration[J]. Fuel, 2023, 331: 125690.

[56]LEE G-J, KWON T-H. Effect of carbon dioxide adsorption on permeability and mechanical strength of coal powders[J]. From Fundamentals to Applications in Geotechnics, 2015: 801–806.

[57]ZAGORŠČAK R, THOMAS H R. Effects of subcritical and supercritical CO2 sorption on deformation and failure of high-rank coals[J]. International Journal of Coal Geology, 2018, 199: 113–123.

[58]RANJITH P G, JASINGE D, CHOI S K, et al. The effect of CO2 saturation on mechanical properties of australian black coal using acoustic emission[J]. Fuel, 2010, 89(8): 2110–2117.

[59]VIETE D R, RANJITH P G. The effect of CO2 on the geomechanical and permeability behaviour of brown coal: implications for coal seam CO2 sequestration[J]. International Journal of Coal Geology, 2006, 66(3): 204–216.

[60]张庆贺, 杨科, 袁亮, 等. 吸附性气体对构造煤的损伤效应试验研究[J]. 采矿与安全工程学报, 2019, 36(5): 995–1001.

[61]CZAPLIŃSKI A, HOŁDA S. Changes in mechanical properties of coal due to sorption of carbon dioxide vapour[J]. Fuel, 1982, 61(12): 1281–1282.

[62]杜秋浩, 刘晓丽, 王维民, 等. 超临界CO2-水-煤相互作用后冲击载荷下煤的动态响应[J]. 煤炭学报, 2019, 44(11): 3453–3462.

[63]ZHONG S, BAITALOW F, NIKRITYUK P, et al. The effect of particle size on the strength parameters of german brown coal and its chars[J]. Fuel, 2014, 125: 200–205.

[64]袁梅, 许江, 李波波, 等. 粒径对含瓦斯型煤力学性质及渗透特性的影响试验研究[J]. 煤矿安全, 2016, 47(9): 24–27.

[65]DONG J, CHENG Y, HU B, et al. Experimental study of the mechanical properties of intact and tectonic coal via compression of a single particle[J]. Powder Technology, 2018, 325: 412–419.

[66]WANG C, CHENG Y, HE X, et al. Size effect on uniaxial compressive strength of single coal particle under different failure conditions[J]. Powder Technology, 2019, 345: 169–181.

[67]李建平, 郑克洪, 杜长龙. 煤和矸石的冲击破碎粒度分布特性[J]. 煤炭学报, 2013, 38(S1): 54–58.

[68]刘送永, 杜长龙, 李建平. 煤截割粒度分布规律的分形特征[J]. 煤炭学报, 2009, 34(7): 977–982.

[69]YU M, WU M, YANG X, et al. Effect of temperature on the evolution and distribution for particle size of loose broken coal during the uniaxial confined compression process[J]. Fuel, 2022, 318: 123592.

[70]李伟, 钟艺, 郭敬杰, 等. 不同类型煤颗粒侧限压缩变形破碎特性试验研究[J]. 煤炭科学技术, 2022, 50(2): 163–170.

[71]ZHANG K, CHENG Y, LI W, et al. Influence of supercritical CO2 on pore structure and functional groups of coal: implications for CO2 sequestration[J]. Journal of Natural Gas Science and Engineering, 2017, 40: 288–298.

[72]程远平, 胡彪. 基于煤中甲烷赋存和运移特性的新孔隙分类方法[J]. 煤炭学报, 2023, 48(1): 212–225.

[73]ZHU W, LIU L, LIU J, et al. Impact of gas adsorption-induced coal damage on the evolution of coal permeability[J]. International Journal of Rock Mechanics and Mining Sciences, 2018, 101: 89–97.

[74]郑克洪, 杜长龙, 邱冰静. 煤矸破碎粒度分布规律的分形特征试验研究[J]. 煤炭学报, 2013, 38(6): 1089–1094.

[75]MANDELBROT B B, WHEELER J A. The fractal geometry of nature[J]. American Journal of Physics, 1983, 51(3): 286–287.

[76]张宗堂, 高文华, 张志敏, 等. 基于Weibull分布的红砂岩颗粒崩解破碎演化规律[J]. 岩土力学, 2020, 41(03): 877–885.

[77]É. GUYON, J. TROADEC J. Du sac de billes au tas de sable[J]. Nature Sciences Sociétés, 1997, 5(2): 77.

[78]HARDIN B O. Crushing of soil particles[J]. Journal of Geotechnical Engineering, 1985, 111(10): 1177–1192.

[79]于际都, 沈超敏, 刘斯宏. 染色石膏颗粒一维压缩破碎与粒径迁移[J]. 岩石力学与工程学报, 2020, 39(05): 1071–1079.

[80]LOUPASAKIS C, ANGELITSA V, ROZOS D, et al. Mining geohazards—land subsidence caused by the dewatering of opencast coal mines: the case study of the amyntaio coal mine, florina, greece[J]. Natural Hazards, 2014, 70(1): 675–691.

[81]UNVER B, YASITLI N E. Modelling of strata movement with a special reference to caving mechanism in thick seam coal mining[J]. International Journal of Coal Geology, 2006, 66(4): 227–252.

[82]冯梅梅, 吴疆宇, 陈占清, 等. 连续级配饱和破碎岩石压实特性试验研究[J]. 煤炭学报, 2016, 41(9): 2195–2202.

[83]尚宏波, 靳德武, 张天军, 等. 三轴应力作用下破碎煤体渗透特性演化规律[J]. 煤炭学报, 2019, 44(4): 1066–1075.

[84]褚廷湘, 李品, 晁江坤, 等. 承压破碎煤体碎胀系数演变特征与机制[J]. 煤炭学报, 2017, 42(12): 3182–3188.