吸附CO_(2)煤体静力学特性及细观损伤破坏特征  

Static mechanical properties and microstructural damage characteristics of CO_(2)adsorbed coal mass

作　　者：王磊[1] 张宇[1] 朱传奇[1] 刘怀谦 陈礼鹏 李少波[1] 吴雨轩 WANG Lei;ZHANG Yu;ZHU Chuanqi;LIU Huaiqian;CHEN Lipeng;LI Shaobo;WU Yuxuan(State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,Anhui University of Science and Technology,Huainan,Anhui 232001,China)

机构地区：[1]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

出　　处：《岩石力学与工程学报》2025年第1期56-68,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金青年项目(52104073);安徽省科技重大专项项目(202203a07020010);省属企业国有资本经营预算项目(HM23719030)。

摘　　要：为探究不同CO_(2)-荷载耦合作用对煤体力学特性及细观损伤破坏特征的影响,采用工业CT扫描系统、MTS 816岩石力学加载装置以及自主研制的气-固耦合试验装置,对原煤开展不同CO_(2)压力条件下的单轴加载试验,分析CO_(2)压力对煤体力学特性、破坏模式的影响,并基于图像处理技术分别从二维、三维尺度探究煤体细观损伤演化特征和裂纹扩展规律,从宏-细观层面揭示煤体对CO_(2)-荷载耦合作用的力学响应机制。结果表明:(1)气-固耦合作用下煤体应力-应变曲线可分为4个典型阶段,且峰值强度和弹性模量均随初始CO_(2)压力增加呈劣化趋势;(2)煤体裂隙扩展可分为裂隙吸附扩展阶段、裂隙压密闭合阶段、新裂隙萌生发育阶段和裂隙快速扩展贯通阶段,裂隙体积、裂隙率和三维分形维数均与气压呈正相关,且受CO_(2)气楔效应影响,受载煤体内部裂隙空间分布复杂化,破坏形式由单一的张拉破坏逐渐转为张拉、剪切共存的复合型破坏;(3)基于三维孔隙率定义了损伤变量,发现其值逐渐由0增至0.34,近似呈指数型上升,且通过对比气-固耦合作用下煤体峰值强度与损伤变量所得的理论强度,验证了损伤变量的合理性。In order to explore the influence of different CO_(2)-load coupling effects on the mechanical properties and meso-damage and failure characteristics of coal mass,the uniaxial loading tests of raw coal under different CO_(2)pressures were carried out by using industrial CT scanning system,MTS 816 rock mechanics loading device and self-developed gas-solid coupling test device.The influence of CO_(2)pressure on the mechanical properties and failure mode of coal was analyzed.Based on image processing technology,the meso-damage evolution characteristics and crack propagation laws of coal bodies are explored from two-dimensional and three-dimensional scales respectively,and the mechanical response mechanism of coal bodies to CO_(2)-load coupling is revealed from the macro-meso-level.The results indicate that:(1)the stress-strain curve of coal mass under gas-solid coupling can be divided into four typical stages,and both peak strength and elastic modulus exhibited a degradation trend with increasing initial CO_(2)pressure.(2)Coal fracture expansion can be divided into fracture adsorption and expansion stage,fracture compaction and closing stage,new fracture initiation and development stage,and fracture rapid expansion and penetration stage,the fracture volume,fracture rate and three-dimensional fractal dimension are positively correlated with CO_(2)pressure,additionally,influenced by the CO_(2)gas wedge effect,the spatial distribution of fractures inside the loaded coal mass becomes complex,and its failure form gradually changes from a single tension failure to a compound failure in which tension and shear coexist.(3)The damage variable was defined based on threedimensional porosity,and it was found that its value gradually increased from 0 to 0.34,approximately exhibiting an exponential rise.By comparing the peak strength of the coal under gas-solid coupling with the theoretical strength obtained from the damage variable,the rationality of the damage variable was validated.

关 键 词：岩石力学 CO_(2)吸附 原煤 静力学特性 细观损伤 破坏特征 

分 类 号：TU45[建筑科学—岩土工程]