Strength and deformation characteristics of compacted silt from the lower reaches of the Yellow River of China under monotonic and repeated loading

• Stress strain relationship and shear strength under monotonic loading were obtained.
• A permanent deformation model under repeated loading was proposed.
• Resilient behaviors under repeated loading were studied.
• The relationship between threshold stress and static failure deviator stress was obtained.

Silt is a widespread deposit in the lower reaches of the Yellow River, China with low plasticity and cohesion and poorly-graded characteristics. It is the primary filling material for subgrades in this region because of the lack of sand and gravel materials. Using the California Bearing Ratio (CBR) method alone to characterize the silt subgrade cannot provide an adequate assessment of its shear behaviors under monotonic and repeated loading. To improve the understanding of the strength and deformation characteristics of silt fill, a series of triaxial tests under monotonic and repeated loading were conducted. Specifically, the variations in the engineering characteristics (such as shear strength, permanent deformation, resilient modulus, and threshold stress) of silt fill caused by changes in the physical and stress states were investigated. Experimental results were used to establish empirical correlations for the strength and deformation parameters. These results provide a basis for the mechanical analysis and design of silt subgrades for stability.