关键词: 结构性黄土, 胶结作用, 压缩特性, 微观结构模型, 非连续变形分析

Abstract: The structure of loess is closely related to its formation process and has an important impact on its physical and mechanical properties. In view of the large pores and cementation features of structured loess, we embedded the clay cementation which plays a major role in structured loess into the existing DDA. By using Monte Carlo method and DDA, we simulated the deposition process of loess, in particular, the collision and friction of particles in the falling process and analyzed the translational and rotational movements of particles in the consolidation process. On this basis, we constructed a microstructural loess model which is close to undisturbed loess in terms of void ratio. Furthermore, we simulated one-dimensional compression test on the structured loess model under different pressures with the extended DDA, and compared with indoor compression test to demonstrate the reliability of the numerical simulation. We found that, despite similar overall trends, the particle displacement of cemented sample was smaller than that of non-cemented sample. Vertical displacement of particles dominated regardless of some differences in the degree and direction of displacements. Major differences existed in different parts, i.e., upper particles underwent larger displacement, while lower particles witnessed smaller displacement.

Key words: structured loess, cementation, compression characteristics, microstructure model, DDA