基于纳米划痕的陆相页岩纹层界面过渡区分布范围定量研究  

Quantitative study on distribution range of interface transition zone in continental shale beddings based on nano scratch

作　　者：杨柳[1,2] 杨铎 何满潮[1,2] YANG Liu;YANG Duo;HE Man-chao(State Key Laboratory for Tunnel Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)隧道工程灾变防控与智能建养全国重点实验室,北京100083 [2]中国矿业大学(北京)力学与土木工程学院,北京100083

出　　处：《岩土力学》2025年第2期353-367,共15页Rock and Soil Mechanics

基　　金：国家自然科学基金面上项目(No.52374014)。

摘　　要：陆相页岩普遍发育黏土质、长英质及方解石质等不同组分的纹层,在水力压裂刺激页岩裂隙网格结构过程中,界面过渡区(interfacialtransitionzone,简称ITZ)的存在严重地影响了裂纹的扩展方向和形态。然而,目前缺乏针对页岩纹层ITZ分布范围的有效量化方法。针对页岩微观力学参数曲线的离散特征,通过置信椭圆标定ITZ范围内的离散数据,使用线性拟合与置信椭圆交点的投影长度作为定量页岩纹层ITZ的新方法。借助扫描电子显微镜与矿物定量评价系统,获得页岩表面形貌和矿物分布情况,对划痕试验后矿物破坏形式进行分析。基于纳米划痕试验结果,通过断裂韧性确定了不同岩性矿物的分布长度,并将其与扫描电子显微镜识别结果进行对比。结果表明:伊利石等塑性矿物在划痕试验过程中呈现出碎屑在两侧堆积的破坏模式,而钠长石和石英等脆性矿物则呈现出锯齿状的破坏或点状的崩裂。由于ITZ的存在,扫描电子显微镜识别出的塑性矿物分布长度大于断裂韧性曲线的定量结果。摩擦系数法受到表面粗糙度的影响,拟合置信度较低,定量结果偏大。与摩擦系数法相比,断裂韧性法具有更高的数据连续性和拟合置信度,但是考虑因素较为单一。无量纲参数法综合考虑了断裂韧性、硬度、摩擦系数和划痕深度的影响,曲线离散度较低,拟合误差较小。相比于传统单个力学参数的识别手段,基于无量纲参数对ITZ分布范围的量化准确度有较大提升。Continental shale generally consists of layers with varying components,including clay,felsic minerals,and calcite.During hydraulic fracturing stimulation of shale fracture network structure,the interfacial transition zone(ITZ)forms,significantly influencing crack propagation direction and morphology.Currently,effective quantitative methods for determining the ITZ distribution range in shale layers are lacking.This study focuses on the discrete characteristics of shale micro-mechanical parameter curves and employs confidence ellipses to calibrate discrete data within the ITZ range.Linear fitting and the projection length of confidence ellipse intersections are introduced as a new method for quantifying the ITZ in shale layers.Scanning electron microscopy and a mineral quantitative evaluation system were used to obtain shale surface morphology and mineral distribution,analyzing mineral damage forms after scratch experiment.Nano scratch experiment results were used to determine mineral distribution lengths from various rock types via fracture toughness,compared with scanning electron microscopy findings.Results show that plastic minerals such as illite show a damage pattern of debris accumulation on both sides during the scratch test,while brittle minerals such as albite and quartz show jagged damage or point-like chipping.The presence of ITZ causes the distribution length of plastic minerals identified by scanning electron microscopy to exceed the quantitative results from fracture toughness curves.The friction coefficient method is affected by surface roughness,resulting in lower fitting confidence and higher quantitative results.Compared to the friction coefficient method,the fracture toughness method offers higher data continuity and fitting confidence,though it considers relatively fewer factors.Non-dimensional parameters comprehensively account for fracture toughness,hardness,friction coefficient,and scratch depth,reducing curve dispersion and fitting errors.Compared to traditional methods for identifying indi

关 键 词：陆相页岩 纳米划痕试验 破坏模式 量纲分析 界面过渡区 

分 类 号：TU456[建筑科学—岩土工程]