Structural Parameter of Structured Soils and Its Application in Constitutive Modeling

Abstract

Structured soils exhibit significantly different mechanical behaviors than reconstituted soils because of the influence of their structure. A theoretical study of the structured soils is carried out in this paper. A newly defined variable—relative structure degree—was used to quantify the integrity of the soil structure during compression based on intrinsic compression curves of the intact structured soils. Also, a new volume change equation for structured soils was developed by using effective stress and relative structure degree as variables. The volume change equation provides the interpretation of the nonlinear compression curve of structured soils in the space of void ratio against logarithmic mean effective stress. The proposed approach for structured soils was extended to the triaxial stress state by introducing equivalent, current, and normal yield surfaces, so that the influence of stress history and soil structure could be considered in the model. The characteristics of the proposed model were illustrated through simulations of the influence of soil structure and stress history. The proposed model was validated by making comparisons between experimental data and model predictions.