Study on the Influencing Factors of the Shear Strength of Shallow Unsaturated Soda-saline Loessal Soil

Abstract

Investigating the shear strength of shallow unsaturated soda - saline loessal soil is meaningful for the evaluation of the stability of shallow slopes in regions where soda - saline loessal soil is distributed. In this study, ring shear tests were carried out on remolded shallow unsaturated soda-saline loessal soil specimens to analyze the influence of water content, clay fraction, and shear rate on the soil’s shear strength. The test results indicate that for specimens with a salt content of 0.5%, when the water content increased from 10% to 22%, the maximum reduction in shear strength reached 12.7%. The corresponding maximum reductions for specimens with salt contents of 1% and 1.5% were 11.9% and 11.7% respectively. The soil’s shear strength exhibited a decreasing with the increase in water content. When the clay content was increased from 8% to 24%, the maximum increases in shear strength for specimens with salt contents of 0.5%, 1%, and 1.5% were 7.8%, 12.2%, and 10.0% respectively. The soil’s shear strength showed an increasing with the increase in clay content. When the shear rate was elevated from 0.1 mm/min to 0.2 mm/min, 0.5 mm/min, 1 mm/min, and 2 mm/min, the shear strength of the 0.5% salt - content specimen decreased from 37.7 kPa to 36.7 kPa, 34.2 kPa, 33.0 kPa, and 31.0 kPa, representing reductions of 2.7%, 3.4%, 3.5%, and 6.1% respectively. The maximum reductions for specimens with 1% and 1.5% salt content were 4.3% and 4.2% respectively. The soil’s shear strength decreased as the shear rate increased. These experimental results offer a parameter foundation for the stability assessment of shallow soda - saline loessal soil slopes.