In Situ X-Ray Computed Tomography (CT) Investigation on Localized Deformation and Crack Damage Evolution in a Bimrock by Tracking Rock Blocks
In Situ X-Ray Computed Tomography (CT) Investigation on Localized Deformation and Crack Damage Evolution in a Bimrock by Tracking Rock Blocks
复制标题
原位x射线计算机断层扫描（CT）追踪岩体局部变形和裂纹损伤演化的研究
DOI：
10.1155/2020/8851817
复制
发表时间：
2020-10
影响因子：
1.8
通讯作者：
H. Meng;Y. Wang;J. Ren
中科院分区：
文献类型：
--
作者：
H. Meng;Y. Wang;J. Ren
块体岩体的失稳往往对地质和生态环境构成威胁，研究块体岩体的局部变形和裂隙损伤演化规律是预测块体岩体灾害的关键。在这项工作中，三轴压缩试验块在基质土（bimsoils）与岩石块的百分比为40%（质量比）下进行断层扫描监测使用原始的实验装置专门设计，以匹配450千伏工业X射线计算机断层扫描（CT）设备。通过在整个测试过程中的关键点以及从样品中的不同位置进行CT扫描来获得一系列二维CT图像。采用块体跟踪运动（BTM）方法跟踪岩石块体变形过程中的运动轨迹，研究了岩石变形过程中的物理应变局部化现象。岩石块体与土体之间的相互作用，包括岩石块体与土体之间的反复接触和分离，对裂隙的分布和形态有很大的影响，并最终形成裂隙的宏观形态。位移矢量分析揭示了岩石块体在变形过程中的空间运动学和相关的局部化带演化，这与宏观裂纹图案观察一致。与低密度区相对应的裂纹进一步表明了局部变形的不均匀性。通过对岩石块体运动的X射线CT分析，探讨了三轴变形条件下岩石的细观结构变化和应变局部化。
Instability of rock mass with block-in-matrix-rocks (bimrocks) often poses a threat to the geological and ecological environment; thus, investigation of the localized deformation and crack damage evolution is critical to predict the bimrock hazards. In this work, triaxial compression testing on block-in-matrix-soils (bimsoils) with a rock block percentage of 40% (mass ratio) was performed under tomographic monitoring using an original experimental setup specially designed to match the 450 kV industrial x-ray Computerized Tomography (CT) apparatus. A series of 2D CT images were obtained by carrying out CT scanning at key points throughout the test and from different positions in the sample. The physical strain localization phenomenon was well investigated using the proposed Block Tracking Movement (BTM) method to track the trajectory of rock blocks during deformation. The distribution and morphology of cracks are strongly influenced by the interactions between the rock block and the soil matrix including the repeating contact and separation between them that finally results in the macroscopic pattern of cracking. The displacement vector analysis revealed the spatial kinematics of rock blocks during sample deformation and the associated localized band evolution, which was consistent with the macroscopic crack pattern observation. The cracks corresponding to the low-density regions in the bimrock sample further indicate the inhomogeneous pattern of localized deformation. The meso-structural changes and strain localization of the bimrock under triaxial deformation are discussed first by analyzing the rock block movement using x-ray CT data.