Investigation on Compressibility and Microstructure Evolution of Intact Loess at Different Wetting States

Loess is widely deposited in arid and semi-arid areas characterized by low dry density, developed pore space, loose structure, which not commensurate with high structural strength shear the state. Many natural phenomena experimental results show that intact loess very sensitive to change of water content, a slight increase content can cause rapid reduction strength. Abundant information available literature for collapsibility loess. However, research on evolution compressibility during wetting, helpful understanding collapsible deformation caused long-term irrigation, remains minimal. To this end, article, at different wetting stages investigated oedometer tests, microstructure size distribution (PSD) were specimens contents before after tests scanning electron microscope (SEM) mercury intrusion porosimetry (MIP) methods. The compression index ( C c ) secondary α depend vertical stress abruptly when exceeds yield stress. / values are constant, increases peak then gradually decreases 0.025. Wetting loading damage loess; specifically, leads collapse overhead structure transformation from bimodal PSD into unimodal PSD, intensifies form compacted interlocking promotes medium pores small pores.