Effects of soil water content and soil sodicity on soil shearing strength

Soil water content and soil sodicity are two important parameters of soil physical and chemical characteristics. Effects of soil water content and soil sodicity on soil shearing strength were carried out in laboratory by triaxial shearing test under unconsolidated-undrained conditions. Five soil exchangeable sodium percentages (ESP) of 0, 5, 10, 20, 40 and four soil water contents(w/w) of 0.05, 0.10, 0.20, 0.34(saturated) were tested. Experimental data indicate that soil cohesive force firstly increases and then decreases with the increase of soil water content, and it reaches to the maximum at the water content of about 0.10. Soil internal frictional angle decreases linearly with the increase of soil water content. The influence mechanism of soil ESP on soil cohesive force is complicated and its effect decreases with the increase of soil water content. The soil ESP influence on soil internal frictional angle is small. The effect of soil water content on soil shearing strength is much greater than that of soil sodicity.