Loess shear failure micro-mechanisms: insights from 3D microstructural evolution and sensitivity analysis

Using X-ray micro-computed tomography and advanced image processing, we comprehensively quantified the three-dimensional microstructure of intact Malan loess, including particle and pore size, shape, and orientation. We analyzed data from different regions of a triaxially sheared loess sample to track the evolution of these microstructural parameters during deformation. To identify the most responsive indicators of loess failure, we assessed the sensitivity of various microstructural parameters using relative entropy. The detailed results directly link macroscopic behavior to microstructural changes, providing a deeper understanding of loess shear failure mechanisms.本研究借助X射线显微计算机断层扫描（X-ray micro-computed tomography）与先进图像处理技术，对完整马兰黄土（Malan loess）的三维微观结构开展了全面量化分析，涵盖颗粒与孔隙的尺寸、形态及取向特征。通过解析三轴剪切黄土试样不同区域的试验数据，追踪了变形过程中上述微观结构参数的演化规律。为明确黄土破坏的最优响应表征指标，本研究采用相对熵（relative entropy）评估了各类微观结构参数的敏感性。本研究的详细结果将宏观力学行为与微观结构变化直接关联，为深入理解黄土剪切破坏机理提供了更深刻的认知支撑。