Disturbed State Concept–Based Constitutive Model for Structured Soils

Abstract

The compression behavior of structured soils after virgin yielding is highly nonlinear and cannot be captured by a single line in the e–ln(p′) space. The slope of the compression curve of structured soils changes gradually as the structure of the soil crashes and reaches to the slope of the same soil in the remolded state. When the initial and final values are known, the disturbed state concept can be used to describe the compression behavior of structured soils. In this study, the state of the structured soil at the beginning of virgin yielding was considered as initially intact, and its state after full destruction was considered as fully adjusted. The compression index of the soil at any particular state between these two states was described using a state function based on the experimental results. A compression model with a variable slope of the compression curve was developed using the distributed state concept. The proposed model was implemented in the modified Cam-clay model and verified using data available in the literature for oedometer and triaxial tests on structured soils. Comparison with the experimental results of triaxial shearing tests showed that the proposed model was able to describe the behavior of specimens with low overconsolidation ratios more accurately.