工程地质学报2024，Vol.32Issue(1)：64-73,10.DOI:10.13544/j.cnki.jeg.2021-0663
干湿循环作用下岩桥破裂演化及前兆异常定量识别研究
RESEARCH ON QUANTITATIVE IDENTIFICATION OF RUPTURE EVO-LUTION AND PRECURSORY ANOMALY OF ROCK BRIDGE UNDER THE WETTING-DRYING CYCLES
摘要
Abstract
To investigate the rupture evolution and precursory anomalies of the rock bridge in a rock slope contai-ning a locking segment under wetting-drying cycles,we conducted uniaxial compression tests on rock bridge speci-mens subjected to different numbers of wetting-drying cycles.Utilizing digital image correlation(DIC)technology,we measured the full-field deformation of the specimens in real-time during the loading process,identifying crack growth types by solving displacement vectors.Additionally,we introduced the covariance matrix to quantitatively describe the discreteness of multiple components of the strain field.A method to identify precursory anomalies in the rock bridge strain field was proposed,and the influence of wetting-drying cycles was analyzed.The results indicate that with an increase in the number of wetting-drying cycles,the crack initiation stress and compressive strength of the rock bridge gradually deteriorate.As cracks develop in the rock bridge,the displacement vectors of surrounding rocks show significant differences,identifying two basic types of cracks:tensile cracks and shear cracks.The axial stresses required for crack initiation and propagation decrease with an increase in the number of wetting-drying cy-cles.The evolution process of the effective variance of the strain field can be divided into three stages:initial differ-entiation,stable differentiation,and accelerated differentiation.When the shear crack initiates,the effective vari-ance of the specimen under dry conditions abruptly increases,while the effective variance of the specimen under wetting-drying cycles shows accelerated growth,serving as a precursor.The precursor stress level and time level of the specimen under wetting-drying cycles are lower than those under dry conditions due to the softening effect in-duced by the wetting-drying cycles.关键词
干湿循环作用/岩桥/数字图像相关/位移矢量/协方差矩阵/前兆Key words
Wetting-drying cycles/Rock bridge/Digital image correlation/Displacement vector/Covariance ma-trix/Precursor分类
天文与地球科学引用本文复制引用
张科,李娜..干湿循环作用下岩桥破裂演化及前兆异常定量识别研究[J].工程地质学报,2024,32(1):64-73,10.基金项目
国家自然科学基金项目(资助号:42362034,11902128),云南省应用基础研究计划项目(资助号:2019FI012).This research is supported by the National Natural Science Foundation of China(Grant Nos.42362034,11902128)and the Applied Basic Research Foundation of Yunnan Province,China(Grant No.2019FI012). （资助号:42362034,11902128）
