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不同超临界CO2浸蚀时间后冲击煤体能量演化与破坏特征OA北大核心CSTPCD

Energy evolution and failure characteristics of impacted coal after varying durations of supercritical CO2 immersion corrosion

中文摘要英文摘要

在未采煤层封存CO2时,注入的CO2受高温高压影响会处于超临界态,影响煤层稳定性.为研究超临界CO2浸蚀后煤体受扰动影响引起的能量耗散与破坏特征,基于自主研发的高压气体吸附/解吸试验系统对煤体开展不同超临界CO2浸蚀时间(0、2、4、6d)的吸附试验,利用分离式霍普金森压杆试验系统对超临界CO2作用后的煤体开展冲击压缩试验,并结合高速摄像仪拍摄了冲击过程,分析了冲击煤体的能量耗散规律,阐明了煤体的破坏裂纹演化与破碎分形特征.研究结果表明:相同冲击荷载下,不同超临界CO2浸蚀时间后煤样的应力-应变曲线变化趋势类似,可划分为弹性能量耗散、塑性能量耗散和峰后能量耗散3个阶段.随超临界CO2浸蚀时间增长,煤样吸能能力减弱,冲击煤样表面裂纹数量增多,裂纹网络及扩展方向逐渐复杂,煤样破碎更加剧烈,破碎粒径减小,破碎形态更加复杂,最后确定了不同浸蚀时间后煤样破碎分形维数与耗能密度的线性相关关系.研究结果对于开展注CO2强化深部煤层气开采工程探索具有一定的理论意义.

When the CO2 is sealed in the unmined coal seam,the injected CO2 will be in a supercritical state due to the influence of high temperature and high pressure,which will reduce the stability of the coal seam.In order to study the energy dissipation and failure characteristics of coal body caused by disturbance after supercritical CO2 immersion corrosion,based on the self-developed high-pressure gas adsorption/desorption experimental system,we conducted adsorption experiments on the coal with different supercritical CO2 immersion corrosion time(0,2,4,and 6 days),and impact compression tests were carried out on the coal after the action of supercritical CO2 by using split Hopkinson pressure bar experimental system,and combined with high-speed videotape camera to film the impact process,to analyze the energy dissipation rules of the impact coal,and to elucidate the destructive cracking evolution and crushing fractal characteristics of the coal.The results show that:the stress-strain curves of coal samples after different supercritical CO2 immersion corrosion time have similar trends under the same impact load,which can be divided into three stages:elastic energy dissipation,plastic energy dissipation,and post-peak energy dissipation.With the increased of supercritical CO2 immersion corrosion time,the energy absorption capacity of coal samples decreased,the number of cracks on the surface of impact coal samples increased,the crack network and propagation direction became more complex,the crushing of coal samples became more intense,the crushing particle size decreased,and the crushing morphology became more complex.Finally,the linear correlation between fractal dimension and energy consumption density of coal samples after different corrosion time was determined.The results of the study have certain theoretical significance for carrying out the exploration of CO2 injection to strengthen the deep coalbed methane extraction project.

王磊;杨震宇;陈礼鹏;王勇;张帅;王安铖;李伟利

安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室,安徽淮南 232001煤炭工业合肥设计研究院有限责任公司,安徽合肥 230041安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室,安徽淮南 232001||煤炭工业合肥设计研究院有限责任公司,安徽合肥 230041

土木建筑

CO2地质封存超临界CO2冲击荷载能量耗散破碎分形

CO2 geological storagesupercritical CO2impact loadingenergy dissipationcrushing fractal

《岩土力学》 2024 (008)

2251-2262 / 12

安徽省科技重大专项项目(No.202203a07020010);省属企业国有资本经营预算项目(No.HM23719030).This work was supported by the Anhui Province Science and Technology Major Special Projects(202203a07020010)and the Budgetary Items for State-owned Capital Operation of Provincial Enterprises(HM23719030).

10.16285/j.rsm.2024.0254

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