A testing procedure and a model for resilient modulus and accumulated plastic strain of cohesive subgrade soils.

摘要

The concept of grouting cohesive subgrade soil specimens to the top and bottom caps of a triaxial cell in the Resilient Modulus test has been examined for different factors, especially the effect of the undrained condition on the measurement of the resilient modulus of a cohesive subgrade soil, which is classified as A-6. Also, the effectiveness of the accompanied inside LVDTs setup, which measures the deformation over the whole length of the specimen, in measuring the axial deformations has been investigated. The effects of loading sequence, rest period, compaction method, stress level, and confining pressure on the resilient modulus have also been studied.;The model is considered a contribution in predicting both the plastic strain at apparent shake down and the resilient modulus of compacted cohesive subgrade soils based on its index properties and the deviator stress at failure from static triaxial test.;The behavior of one A-6 cohesive subgrade soil under repeated loadings has been investigated by testing twelve compacted specimens at different molding water contents and stress levels. This has been achieved by studying the behavior of both the resilient and plastic strains of the tested soil under repeated loadings. A statistical model, which relates both the plastic and resilient strains at the apparent stability state (Shake Down) to some of the soil index properties, has been developed. The model has been tested against another soil, which is classified as A-5 according to AASHTO system, under different confining pressures and two ages. The model has adequately predicted the M