关键词: 氯盐渍粉砂, 压缩特性, 三轴试验, 扫描电镜

Abstract: Salt content is a significant factor of the mechanical properties of saline soils. This study investigates saturated chloride saline silty sands that are artificially prepared, focusing on salt content-related influences on their compression and shear properties and the underlying micro-mechanisms, through conducting oedometer tests, triaxial tests, and scanning electron microscopy (SEM). Results reveal that at a salt content below saturation, the compression index increases linearly with it, while the compression modulus decreases gradually. Above the saturation threshold, this index is steady, and the modulus exhibits minor fluctuations. The rebound index remains independent of salt content. Under drained consolidation, stress-strain relationships show limited sensitivity to salt content, whereas volumetric strain increases with it. In undrained consolidation tests, both stress-strain relationships and pore pressure development are governed by the interplay of salt content and confining pressure. Microstructural analysis demonstrates that salt crystallization induces dual mechanisms of interparticle cementation and pore-filling, and the number of micropores increase with the increasing salt content. Our findings would help develop a constitutive model, practically useful for engineering construction in saline soil regions.

Key words: chloride saline silty sand, compression property, triaxial test, scanning electron microscopy