岩石轴压CT图像的分区损伤信息与临界破坏识别  

Zonal damage information and critical failure identification of CT images of rock under triaxial compression

作　　者：刘树新 邢杰 郑旭 陈世杰[2] LIU Shu-xin;XING Jie;ZHENG Xu;CHEN Shi-jie(Mining Institute of Inner Mongolia University of Science and Technology,Baotou 014010,China;Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]内蒙古科技大学矿业研究院,内蒙古包头014010 [2]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《岩土工程学报》2021年第3期432-438,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51264028);内蒙古自治区高等学校科学研究项目(NJZY11147)。

摘　　要：岩石三轴压缩试验过程中虽然损伤不断积累,但宏观破坏前其CT图像却没有明显的变化,因此在峰值前仅通过CT数难以准确分析其损伤破坏信息。为了识别岩石的损伤信息及临界破坏特征,将轴压过程中的砂岩CT图像进行分区,使用位置线上灰度的变化代表分区内灰度的变化。CT图像中某一位置线上灰度值的变化曲线是一种起伏、粗糙的曲线,利用描述粗糙曲线的分形Rd指标定量分析砂岩损伤规律,并基于CT图像上全部位置线的Rd值总和来定义损伤变量,用其表征砂岩的损伤程度。计算结果表明荷载水平在0.84左右时,Rd值波动大,损伤变量加速增大,表明损伤进入了加速发展阶段,岩石处于损坏破坏的临界状态。由此可以合理地预测岩石的损伤破坏。The CT image and value do not change obviously before the macro-failure under triaxial compression experiments on rock during damage accumulation, so it is difficult to analyze accurately the damage information only through the change of CT number. In order to identify the damage information and critical failure characteristics of sandstone, the CT image is partitioned, and the change of grey level on the position line is used to represent the change of the gray level in the subarea. The grey value curve is a rough curve representing grey change of a certain location online in the CT image. It is used to describe quantitatively the rules of sandstone damage by fractal Rd index, the damage variable is defined as the sum of Rd value of all the position line in the CT image, and it reflects the damage degree of rock. The calculated results show that when the load is about 0.84, the value of Rd has obvious fluctuations and the damage variable increases rapidly, which denotes that the damage has entered a phase of accelerated development, and the rock is in a critical damage state. The proposed method can be used to predict reasonably the damage and failure of rock.

关 键 词：砂岩 CT图像 分形指标 临界损伤信息 

分 类 号：TU452[建筑科学—岩土工程]