煤体微观力学特性的纳米压痕实验研究  

Study on nano-mechanical behavior of coal using nanoindentation tests

作　　者：刘鹏[1,2] 赵渝龙 聂百胜 柳先锋 邓博知 何珩溢 曹明伟 LIU Peng;ZHAO Yulong;NIE Baisheng;LIU Xianfeng;DENG Bozhi;HE Hengyi;CAO Mingwei(College of Resources and Safety Engineering,Chongqing University,Chongqing 400044,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China;School of Emergency Management and Safety Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]重庆大学资源与安全学院,重庆400044 [2]重庆大学煤矿灾害动力学与控制全国重点实验室,重庆400044 [3]中国矿业大学(北京)应急管理与安全工程学院,北京100083

出　　处：《煤炭学报》2024年第8期3453-3467,共15页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(52274173,52204206)。

摘　　要：煤体力学性质的测定与研究对煤炭高效开采和灾害预防具有重要的理论价值。煤较为松软破碎,强度较低,难以制备标准的力学测试煤样,也无法回收利用从而进行重复测试。亟需探索新的力学测试方法完善煤的力学特性研究。纳米压痕技术可以测定小尺度煤体微观力学特性,具有样品易制作、实验快速、样品无损的特点。结合矿物组分测试、形貌扫描和纳米压痕实验,研究了4种煤的物性特征及微观力学性质。结果表明,实验煤样矿物类别主要包括非晶态有机质和黏土、石英和碳酸盐类矿物,不同煤的矿物组分有显著差异。煤的3D形貌图显示不同煤表面粗糙度差异明显,煤中矿物分布具有显著非均质性。纳米压痕实验结果表明:①煤样中石英和碳酸盐类矿物质量分数越高,会导致煤样表面力学性质越强,压痕深度越小;②煤样表面的组分越复杂,煤的非均质性越明显,表面微观力学性质分布的离散程度越高;③煤的煤阶越高,变质程度越高,外部孔隙越发育,导致断裂韧度提高;④对压痕试验结果进行拟合,发现弹性模量与坚固性系数、弹性模量与断裂韧度均具有明显的线性关系,并且弹性模量与断裂韧度的线性关系受峰值载荷的影响。The measurement and research on the mechanical properties of coal bodies have important theoretical value for efficient coal mining and disaster prevention.Coal is relatively soft and fragmented,with low strength,making it difficult to prepare standard mechanical test coal samples and impossible to be recycled for repeated testing.There is an urgent need to explore new mechanical testing methods for improving the research on the mechanical properties of coal.Nanoindentation technology can measure the micro mechanical properties of small-scale coal,which has the characteristics of easy sample preparation,fast experiment,and no damage to samples.The physical and micro-mechanical properties of four coals are investigated with the mineral composition testing,morphological scanning and nanoindentation tests.The results show that the minerals of coal samples mainly include amorphous organic matter,clay,quartz and carbonate minerals,and there are significant differences in the mineral compositions of different coals.The 3D morphology of coals indicates that there are huge differences in surface roughness between different coals, and the distribution of minerals in coals exhibits significant heterogeneity. The results of nanoindentation test show that: ① the higher the mass fractions of quartz and carbonate minerals in coal samples, the stronger the surface mechanical properties of samples and the smaller the in-dentation depth;② the more complex the components on the surface of samples, the more obvious the heterogeneity of coal, and the higher the degree of dispersion of surface micro mechanical properties distribution;③ the higher the rank of coal, the higher the degree of metamorphism, and the more developed the external pores, leading to an increase in fracture toughness;④ fitting the indentation test results reveal a significant linear relationship between elastic modulus and hard-ness, as well as between elastic modulus and fracture toughness. The linear relationship between elastic modulus and frac-ture t

关 键 词：煤体力学性质 纳米压痕 表面形貌 峰值载荷 坚固性系数 弹性模量 断裂韧度 

分 类 号：TD713[矿业工程—矿井通风与安全]