摘要
为探究冲击荷载下含瓦斯煤体动态响应差异,利用可视化含瓦斯煤分离式霍普金森压杆试验系统,对不同初始瓦斯压力下的煤体进行动态冲击试验,分析了不同瓦斯赋存状态下煤体能量耗散规律,并借助超高速摄像机和数字图像相关(digital image correlation,简称DIC)技术阐述冲击过程含瓦斯煤表面裂纹演化特征,结合分形理论获得了瓦斯压力对破碎煤体分形特征的影响,揭示了瓦斯赋存状态与破碎煤体特征尺寸的内在联系。结果表明:冲击荷载下,含瓦斯煤体应力-应变曲线基于能量耗散规律大致可分为4个阶段,瓦斯对煤体劣化作用显著,破碎耗能与破碎耗能密度随初始瓦斯压力增加均呈指数函数减小;受瓦斯气楔效应影响,冲击荷载下含瓦斯煤体应变场演化更为复杂,煤体破坏逐步从横向层裂破坏演变为横向层裂-纵向劈裂的复合型破坏;瓦斯压力作用下,煤体内部损伤加剧,破坏失稳后,破碎煤体平均粒径及破碎块度尺寸随初始瓦斯压力增加而逐渐减小,但分形维数呈指数函数增加,煤体破碎程度更加剧烈;构建了基于煤体破碎过程中能量消耗守恒的多维动态含瓦斯煤破碎模型,结合试验数据验证了模型的合理性,可较好地描述受瓦斯影响下的破碎煤样特征尺寸。研究成果对矿井煤岩瓦斯动力灾害防治具有重要的理论意义和一定的应用前景。
In order to explore the difference in dynamic response of gas-bearing coal under impact loading,an observable gas-bearing coal split Hopkinson pressure bar(SHPB)test system was used to conduct uniaxial impact tests on coal bodies with different initial gas pressures.The energy dissipation law of the coal under different gas occurrence states was analyzed,and with the help of ultra-high-speed camera and digital image correlation(DIC)technology,the evolution characteristics of cracks on the surface of gas-bearing coal during the impact process were demonstrated.Combined with fractal theory,the influence of gas pressure on the fractal characteristics of crushed coal was obtained,and the intrinsic relationship between gas occurrence state and the characteristic size of crushed coal was revealed.The results show that under the impact loading,the stress-strain curve of the gas-bearing coal could be roughly divided into four stages based on the energy dissipation law.The deterioration effect of gas on the coal body was significant,and the crushing energy dissipation and crushing energy dissipation density function decreased exponentially with the increase of the initial gas pressure.Under the gas wedge effect,the evolution of the strain field of the gas-bearing coal subjected to the impact loading was more complicated,and the coal body damage gradually evolved from the transverse splitting failure to the composite transverse splitting-longitudinal splitting failure.Under the action of gas pressure,the internal damage of the coal body was intensified.After the failure,the average particle size and fragmented block size of the fragmented coal body gradually decreased with the increase in initial gas pressure.However,the fractal dimension increased exponentially,and the degree of coal body crushing was more intense.A multi-dimensional dynamic gas-bearing coal crushing model based on the conservation of energy consumption in the coal body crushing process was constructed,and combined with experimental data,the model was validated and it could better describe the characteristic dimensions of fragmented coal samples under the influence of gas.The research results have important theoretical significance and certain application prospects for the prevention and control of dynamic disasters in gas-bearing coal mines.
作者
王磊
张帅
刘怀谦
陈礼鹏
朱传奇
李少波
王安铖
WANG Lei;ZHANG Shuai;LIU Huai-qian;CHEN Li-peng;ZHU Chuan-qi;LI Shao-bo;WANG An-cheng(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;School of Energy and Mining Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2023年第7期1901-1915,共15页
Rock and Soil Mechanics
基金
安徽省高校协同创新资助项目(No.GXXT-2020-055)
安徽省科技重大专项项目(No.202203a07020010)
国家重点研发计划资助项目(No.2020YFB1314203)
深部煤矿采动响应与灾害防控国家重点实验室开放基金课题(No.SKLMRDPC22KF10)。
关键词
含瓦斯煤
冲击荷载
能量耗散
数字图像相关
分形特征
破碎模型
gas-bearing coal
impact loading
energy dissipation
digital image correlation(DIC)
fractal characteristics
crushing model
