Effects of Salt Content on Shear Properties and Microstructure of Stabilized Sulphate Saline Soil

Due to evaporation and capillarity effetcs， salt crystallizes and accumulates in the surface layer of soils in northwest China. The salt particles weaken the stability of the soil and lead to the decline of the shear resistance. Triaxial compression tests and SEM tests were carried out to study the effects of salt content on the shear properties and microstructure of the stabilized saline soil with a salt content of 0.3%-5%. With the increase of salt content， the shear strength first increasesd and then decreased， reaching its peak at 1.5% salt content， which was due to the combined effect of salt particles filling the pores and salt cementation. For the saline soil with a salt content of 1.5%-3%， excessive salt particles played a major role in salt swelling， and a few micro-cracks appeared in the soil sample. At this time， the cohesion and internal friction angle of the saline soil decreased. The saline soil with a salt content exceeding 3% exhibited a strong salt swelling effect， and there were many micro-cracks in the soil sample， making it impossible to conduct triaxial compression tests. The saline soil with a salt content below 1.5% can be stabilized by lime in engineering. In order to prevent the salt content of the soil from increasing， engineering measures should be taken to control evaporation and salt accumulation.