Abstract: It is of great significance for engineering construction and environmental protection to improve saline soil by curing technology to make it an excellent roadbed filler. In this paper, taking light solidified saline soil as the research object, laboratory tests were carried out by using true triaxial apparatus. The effects of the ratio of intermediate principal stress, salt content and confining pressure on the stress-strain relationship, failure strength and shear strength index were analyzed. The strength failure mode of light solidified saline soil was revealed and the calculation method of strength index was established. The test results showed that the slope of the stress-strain curve increases with the increase in the ratio of the intermediate principal stress and the confining pressure, but the salt content has little effect on it. The salt content has a significant effect on the failure stress. When the salt content is at 4%, the failure stress reaches the maximum. Under different conditions, the light solidified saline soil could produce different strength failure modes of lateral expansion, taper, oblique crack, and diagonal. Through analysis and calculation, the prediction formula of failure strength and shear strength index of light solidified saline soil considering the ratio of intermediate principal stress and salt content was established. The comparison showed that the Mohr-Columb strength criterion is conservative in describing the strength of light solidified saline soil and it tends to underestimate the actual strength of the soil. The research results can provide references for engineering practice.

Key words: light solidified saline soil, intermediate principal stress ratio, salt content, breaking strength, shear strength index