基于数字体图像相关法的砂浆内部微裂隙识别与量化  

IDENTIFICATION AND QUANTIFICATION OF MICRO-CRACKS IN MORTAR UPON DIGITAL VOLUME CORRELATION

作　　者：毛灵涛[1] 苏方圆 刘海洲 刘昱清 MAO Ling-tao;SU Fang-yuan;LIU Hai-zhou;LIU Yu-qing(State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources,China University of Mining&Technology,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining&Technology,Beijing 100083,China;School of Transportation,Civil Engineering&Architecture,Foshan University,Foshan,Guangdong 528225,China)

机构地区：[1]中国矿业大学(北京)煤炭精细勘探与智能开发全国重点实验室,北京100083 [2]中国矿业大学(北京)力学与土木工程学院,北京100083 [3]佛山科学技术学院交通与土木建筑学院,广东佛山528225

出　　处：《工程力学》2025年第5期169-183,共15页Engineering Mechanics

基　　金：国家重点研发计划项目(2022YFC2904102);中央高校基本科研业务费项目(2022YJSMT04)。

摘　　要：结合微CT原位加载扫描,利用数字体图像相关法实现了砂浆试件内部亚体素级微裂隙的识别与量化。利用微CT原位加载系统获得了单轴压缩条件下砂浆试件在不同阶段的体图像,对其破坏特征进行了分析;介绍了正则化全局数字体图像相关法和微裂隙识别原理,分析评价了位移场测量及微裂隙识别精度;基于试件的体图像,计算得到了其内部的三维位移场,由灰度残差及最大主应变识别损伤单元,设定损伤因子,对新生微裂隙演化进行了识别与量化。结果表明:引入正则化条件及损伤因子,提高了全局数字体图像相关法的测量精度,实现了亚体素级新生微裂隙的识别与量化;试件的位移场及应变场精细化显示出内部孔隙及裂隙周边变形的局部化特征;试件局部区域在弹性阶段已出现亚体素级微裂隙,在塑性阶段及破坏初期,新生的亚体素级微裂隙占比高于体素级微裂隙。该文研究为混凝土内部微裂隙的识别与量化提供了新的思路与方法。Combined with micro-CT in-situ loading scanning,a digital volume correlation was used to identify and quantify sub-voxel level micro-cracks in a mortar sample.The three-dimensional volumetric images of mortar specimens under different uniaxial compression stages were acquired by using a micro-CT in-situ loading system,and the failure characteristics were analyzed.The regularized global digital volume correlation and the principle of micro-crack identification were presented,and then the measurement precision and micro-crack identification were evaluated and analyzed.Based on the 3D displacement fields,the damaged elements were identified in consideration of gray level residual and maximum principal strain,and then the damage factor was defined to identify and to quantify the evolution of nascent micro-cracks.The results show that the introductions of the regularization and damage factor improve the measurement accuracy of the global digital volume correlation and detect nascent sub-voxel level micro-fractures.The fine displacement fields and strain fields clearly depict the localized deformation characteristics around pores and fractures in the sample.In the local region of the sample,subvoxel-level micro-fractures occur in the elastic stage,and the proportions of nascent subvoxel-level micro-fractures in the plastic stage and the early stage of destruction are higher than those of voxel-level micro-fractures.This study provides both a new idea and a method for the identification and quantification of micro-cracks in concrete.

关 键 词：混凝土 砂浆 微裂隙 数字体图像相关法 微CT 

分 类 号：TU528[建筑科学—建筑技术科学]