Heterogeneity induced strain localization in block-in-matrix-soils subjected to uniaxial loading using real-time CT scanning

查看全文 作　　者：Yanfang [1,2,3]Wu;Xiao [1,2,3]Li;Luqing [1,2,3]Zhang;Shengwen [1,2,3]Qi;Jian [4]Zhou;Jianming [1,2,3]He;Zhaobin [1,2]Zhang;Xiukuo [1,2,3]Sun 机构地区：[1]Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing,100029,China;[2]University of Chinese Academy of Sciences,Beijing,100049,China;[3]Innovation Academy for Earth Science,CAS,Beijing,100029,China;[4]Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology,Beijing,100124,China 出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》索引2023年第15卷第8期,共9页 基　　金：This work was supported by the National Natural Science Foundation of China(Grants Nos.41972287 and 42090023);the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0904). 摘　　要：Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bimsoils because of the heterogeneity,chaotic structure,and lithological variability.As a result,only very limited laboratory studies have been reported on the evolution of their internal deformation.In this study,the deformation evolution of bimsoils under uniaxial loading is investigated using real-time X-ray computed tomography(CT)and image correlation algorithm(with a rock block percentage(RBP)of 40%).Three parameters,i.e.heterogeneity coefficient(K),correlation coefficient(CC),and standard deviation(STD)of displacement fields,are proposed to quantify the heterogeneity of the motion of the rock blocks and the progressive deformation of the bimsoils.Experimental results show that the rock blocks in bimsoils are prone to forming clusters with increasing loading,and the sliding surface goes around only one side of a cluster.Based on the movement of the rock blocks recorded by STD and CC,the progressive deformation of the bimsoils is quantitatively divided into three stages:initialization of the rotation of rock blocks,formation of rock block clusters,and formation of a shear band by rock blocks with significant rotation.Moreover,the experimental results demonstrate that the meso-motion of rock blocks controls the macroscopic mechanical properties of the samples. 关 键 词：Image correlation algorithm Damage processing Real-time computed tomography(CT) imaging Rock block motion Uniaxial compression