An Experimental and Numerical Investigation of the Characteristics and Mechanism of Spacing Cracks in Loess Considering the Size Effect

Loess is a special soil with high water sensitivity which covers a large area in Northwest China. Cracks are prone to generate in loess under the arid and semiarid climates, which will provide a preferential channel for water and reduce the mechanical properties of soils. It is of great significance to understand the evolution characteristics and mechanisms of the cracks in loess areas. At present, research on cracks in soils mainly concentrates on the characteristics of different cracking patterns. However, spacing cracks are mostly discussed in materials like rock and concrete rather than soils. The cracking characteristics and mechanisms of spacing cracks in loess are still inadequate. In this research, drying tests of loess are carried out with different sizes of specimens. The parameters of spacing cracks and local strain distributions of the loess samples are obtained via PCAS and DIC methods during desiccation, respectively. The cracking modes, spacing cracking laws like insertion, and the saturation of spacing cracks are revealed. Finally, the size effect on the characteristics of spacing cracks is verified with the discrete element software MatDEM.