Abstract:

The influences of stress and water content on the subgrade resilient modulus were studied by constructing the prediction model. According to the results of repeated loading tri-axial test, the control indicator was researched. The results showed that the resilient modulus presented different changes with the volume stress increasing, which was unsuitable to reflect the stress dependent of resilient modulus. The confining pressure and the deviatoric stress were more appropriate to be the control indicators. Based on the soil water characteristic curve, the relationship between matric suction and water content was analyzed, and the matric suction was used in the prediction model to express the influence of the water content on the resilient modulus. The model could couple the stress dependence and water sensitivity, and also could well reflect the effects of stress and water, which was verified by the experimental results fitting.

Key words: unsaturated silt soil, stress dependence, water sensitivity, coupling analysis