红页岩纳米压痕细观力学特性研究  

A nanoindentation-based study on the micromechanical properties of red shales

作　　者：周浪 马振乾[2] 黄青荣 帅运林 张吉民 刘荣科 ZHOU Lang;MA Zhenqian;HUANG Qingrong;SHUAI Yunlin;ZHANG Jimin;LIU Rongke(State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,Shenzhen University,Shenzhen 518060,China;Mining College,Guizhou University,Guiyang 550025,China)

机构地区：[1]深圳大学深地工程智能建造与健康运维全国重点实验室,广东深圳518060 [2]贵州大学矿业学院,贵州贵阳550025

出　　处：《煤田地质与勘探》2024年第11期96-107,共12页Coal Geology & Exploration

基　　金：国家杰出青年科学基金项目(52225403);国家自然科学基金地区基金项目(52164003)。

摘　　要：【目的】通过纳米压痕试验研究矿物细观力学特性,对于揭示矿物细观尺度破坏机制具有重要意义。【方法】以磷矿红页岩围岩主要矿物为对象,采用X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS)试验对红页岩主要矿物进行定性、半定量和空间分布特征分析,开展靶向纳米压痕试验,获取矿物细观力学性质。基于Voronoi多边形法构建细观矿物纳米压痕离散数值计算模型,并将模拟结果与试验结果进行对比分析。【结论和结果】结果表明:(1)红页岩中含石英、钠长石、绿泥石和伊利石4种矿物,弹性模量依次为95.62、78.13、53.50、48.91 GPa,石英、钠长石矿物力学性质最好,绿泥石和伊利石最差,表明红页岩非均质性、多相性的材料属性。(2)室内试验表明矿物内部缺陷、微孔隙的存在导致荷载-位移曲线台阶拐点等异常情况,而模拟结果表明矿物颗粒簇尺寸、含量和空间分布特征均会使荷载-位移曲线出现拐点突增等情况,解释了纳米压痕荷载-位移曲线出现异常点的原因。(3)矿物压入后在微裂纹类别、数量、占比及倾向分布的差异较大,表征受载过程矿物劣化程度及微裂纹扩展方向。研究成果有助于预测矿物受荷载作用时的开裂方向,为细观矿物劣化分析提供理论支持,对相似工况下围岩灾害预防提供借鉴。[Objective]Investigating the micromechanical properties of minerals using nanoindentation tests is of great significance for revealing the microscale mechanisms behind mineral failure.[Methods]Focusing on the primary minerals in the surrounding rocks of red shales in a phosphate deposit,this study conducted qualitative and semi-quantitative analyses of these minerals,including their spatial distributions,using X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and targeted nanoindentation tests,determining the micromechanical properties of the minerals.This study developed a discrete numerical calculation model for the microscopic nanoindentation of minerals based on Voronoi tessellation and compared the simulation results with the test results.[Results and Conclusions]The results indicate that the red shales contain four minerals,i.e.,quartz,albitite,chlorite,and illite,which exhibit elastic modulus of 95.62,78.13,53.50,and 48.91 GPa,respectively.Among them,the quartz and albitite minerals exhibit the most favorable mechanical properties,while the chlorite and illite display the worst mechanical properties,indicating that the red shales are heterogeneous and multiphase materials.Laboratory tests indicate that anomalies such as inflection points with a stepped distribution pattern in the load-displacement curves were formed by the presence of internal defects and micropores in minerals. In contrast, the simulation results show that the sharp increase inthe inflection point number of the load-displacement curves was caused by the sizes, content, and spatial distributions ofmineral particle clusters. The minerals differed greatly in the type, quantity, proportion, and inclination distributions ofmicrocracks after mineral impression. This can be employed to characterize the deterioration degree and microcrackpropagation direction of the minerals during loading. The results of this study assist in predicting the cracking directionsof minerals under loads, provide theoretical

关 键 词：红页岩 细观力学特性 纳米压痕试验 Voronoi离散元法 矿物劣化 

分 类 号：P589.1[天文地球—岩石学]