温度冲击下煤的微观结构变化与断裂机制

doi:10.16285/j.rsm.2017.1562

岩土力学 ›› 2019, Vol. 40 ›› Issue (2): 529-538.doi: 10.16285/j.rsm.2017.1562

温度冲击下煤的微观结构变化与断裂机制

王登科^{1, 2, 3, 4}，孙刘涛^{1, 3}，魏建平^{1, 3, 4}

1. 河南理工大学河南省瓦斯地质与瓦斯治理重点实验室-省部共建国家重点实验室培育基地，河南焦作 454000； 2. 中国矿业大学深部岩土力学与地下工程国家重点实验室，江苏徐州 221116； 3. 河南理工大学安全科学与工程学院，河南焦作 454000； 4. 河南理工大学煤炭安全生产河南省协同创新中心，河南焦作 454000

收稿日期:2017-07-25 出版日期:2019-02-11 发布日期:2019-02-14
作者简介:王登科，男，1980年生，博士, 教授，博士生导师，主要从事安全科学与工程的工作。
基金资助:
深部岩土力学与地下工程国家重点实验室开放基金（No. SKLGDUEK1814）；国家自然科学基金（No. 51774118）；教育部“创新团队发展计划”（No. IRT_16R22）；国家重点研发计划项目（No. 2017YFC0804207）；河南省教育厅高校重点科研项目（No. 18A620001）；河南理工大学自然科学基金资助项目（No. J2018-1）

Microstructure evolution and fracturing mechanism of coal under thermal shock

WANG Deng-ke^{1, 2, 3, 4}, SUN Liu-tao^{1, 3}, WEI Jian-ping^{1, 3, 4}

1. State Key Laboratory Cultivation Base for Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo, Henan 454000, China; 2. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining & Technology, Xuzhou, Jiangsu 221116, China; 3. School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan 454000, China; 4. The Collaborative Innovation Center of Coal Safety Production of Henan, Henan Polytechnic University, Jiaozuo, Henan 454000, China

Received:2017-07-25 Online:2019-02-11 Published:2019-02-14
Supported by:
This work was supported by the State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining & Technology (SKLGDUEK1814), the National Natural Science Foundation of China (51774118), the Innovation Team Development Plan of Ministry of Education of China (IRT_16R22), the National Key R&D Program of China(2017YFC0804207), the Key Scientific Research Projects of Henan Provincial Education Department (18A620001) and the Science Research Funds of Henan Polytechnic University (J2018-1).

摘要/Abstract

摘要： 为研究温度冲击下煤的微观结构变化及其损伤断裂机制，以干燥颗粒煤为研究对象，分别开展了煤样的冷冲击和热冷冲击试验。利用扫描电镜（SEM）观测图像结果，分析对比了两种温度冲击前后煤样微观形貌、裂缝分布、开裂和延伸情况，结合断裂力学理论分析了煤样内部微裂缝的开裂机制和扩展方向，并通过ANSYS有限元软件模拟了微裂缝扩展时的应力场和位移场的分布情况，揭示了煤样的断裂机制。研究结果表明，两种温度冲击对煤的结构均造成了不同程度的破坏，温度冲击所形成的热应力最终导致了原始裂纹和新生裂纹的扩展和延伸；温度冲击下所产生的裂纹形式主要有沿晶裂纹、穿晶裂纹、翼型裂纹、交叉裂纹、枝须状裂纹和网状裂纹；分析结果表明，温差愈大，所产生的温度热应力愈大，热冷冲击所产生的裂缝的数量更多、扩展更充分，对煤样的破坏更严重，因此，热冷冲击的破煤效果更好。

关键词: 温度冲击, 微观结构, 断裂机制, 应力强度因子, 破煤效果

Abstract: To study the microstructure change of coal and its damage and fracturing mechanism under temperature shock, cold impact and hot-cold impact tests were carried out on dry granular coal. The micro-morphology, fracture distribution, cracking and extension of coal samples before and after temperature impact were analyzed and compared by scanning electron microscopy (SEM). The cracking mechanism and propagation direction of micro-cracks in coal samples were analyzed based on fracture mechanics theory. The distributions of stress and displacement fields during micro-crack propagation were simulated by ANSYS finite element software to reveal the fracturing mechanism of coal samples. The results showed that the structure of coal was destroyed by two types of temperature shocks, and the thermal stress induced by temperature shocks eventually led to the expansion and extension of the original crack and the new crack. The main types of cracks induced by temperature impact were intergranular crack, transgranular crack, airfoil crack, cross crack, dendritic whisker crack and mesh crack. It is revealed that a bigger temperature difference results in a higher thermal stress. Hot-cold impact can generate more cracks and more extensive crack propagation than cold impact, leading to more serious damage of coal samples. Therefore, the hot-cold impact has better coal breaking effect than the cold impact.

Key words: thermal shock, microstructure, fracture mechanism, stress intensity factor, coal breaking effect

中图分类号:

TD 821

王登科, 孙刘涛, 魏建平, . 温度冲击下煤的微观结构变化与断裂机制[J]. 岩土力学, 2019, 40(2): 529-538.

WANG Deng-ke, SUN Liu-tao, WEI Jian-ping, . Microstructure evolution and fracturing mechanism of coal under thermal shock[J]. Rock and Soil Mechanics, 2019, 40(2): 529-538.

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温度冲击下煤的微观结构变化与断裂机制

Microstructure evolution and fracturing mechanism of coal under thermal shock

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