The formation of compaction bands in porous brittle rocks such as sandstones and carbonates has a significant impact on the localization mechanisms preceding earth and planetary surface instabilities such as earthquakes, landslides, and plate boundary faults. The micromechanics underpinning the dynamics of the formation of compaction bands and its effect on alteration of pore fluid pathways are not yet fully understood. The current study seeks to understand the mechanical properties of compaction in highly porous carbonate at micro- and macro-scale using time-lapse triaxial experiments in an X-ray transparent flow and deformation cell. Images were obtained with increasing axial strain levels using X-ray computed tomography allowing mapping of the evolution of internal structures. In addition to the X-ray analysis, digital image correlation (DIC) was used to quantify the evolution of strain and precisely identify the nucleation mechanism of compaction bands and its dynamics. The effect of friction on the boundary platens was shown to be minimal as evidenced by shear strain obtained from DIC analysis. This comprehensive analysis allowed assessment of the role of heterogeneity for the initiation of compaction bands. Local regions with high porosity provide the initial seeds for discrete compaction followed by the nucleation of traveling waves that lead to diffuse growth of the compaction zone. This interesting phenomenon is expected to be a fundamental mode of compressional deformation in porous brittle media where discrete, often periodic, deformation bands are observed on compaction.

中文翻译：

---

高度多孔碳酸盐中压实带的动态演化：局部非均质性对成核和扩散的作用

多孔脆性岩石（例如砂岩和碳酸盐）中压实带的形成对诸如地震，滑坡和板块边界断层等地球和行星表面不稳定性之前的定位机制具有重大影响。尚不完全了解压实带形成动力学及其对改变孔隙流体路径的影响的微力学。当前的研究试图在X射线透明的流动和变形单元中使用延时三轴实验，以微观和宏观的角度了解高度多孔碳酸盐的压实力学性质。使用X射线计算机断层扫描，随着轴向应变水平的提高，获得了图像，从而可以绘制内部结构的演变图。除了X射线分析之外，数字图像相关技术（DIC）用于量化应变的演变并精确识别压实带的成核机理及其动力学。由DIC分析获得的剪切应变证明，摩擦对边界压板的影响极小。这项全面的分析可以评估异质性在压实带开始过程中的作用。具有高孔隙率的局部区域为离散压实提供了初始种子，随后是行波形核，从而导致压实区的扩散。这种有趣的现象有望成为多孔脆性介质中压缩变形的基本模式，在压缩过程中会观察到离散的，通常是周期性的变形带。由DIC分析获得的剪切应变证明，摩擦对边界压板的影响极小。这项全面的分析可以评估异质性在压实带开始过程中的作用。具有高孔隙率的局部区域为离散压实提供了初始种子，随后是行波形核，从而导致压实区的扩散。这种有趣的现象有望成为多孔脆性介质中压缩变形的基本模式，在压缩过程中会观察到离散的，通常是周期性的变形带。由DIC分析获得的剪切应变证明，摩擦对边界压板的影响极小。这项全面的分析可以评估异质性在压实带开始过程中的作用。具有高孔隙率的局部区域为离散压实提供了初始种子，随后是行波形核，从而导致压实区域的扩散生长。这种有趣的现象有望成为多孔脆性介质中压缩变形的基本模式，在压缩过程中会观察到离散的，通常是周期性的变形带。具有高孔隙率的局部区域为离散压实提供了初始种子，随后是行波形核，从而导致压实区域的扩散生长。这种有趣的现象有望成为多孔脆性介质中压缩变形的基本模式，在压缩过程中会观察到离散的，通常是周期性的变形带。具有高孔隙率的局部区域为离散压实提供了初始种子，随后是行波形核，从而导致压实区的扩散。这种有趣的现象有望成为多孔脆性介质中压缩变形的基本模式，在压缩过程中会观察到离散的，通常是周期性的变形带。