Modified unified critical state model for soils considering over-consolidation and cyclic loading behaviours

Area of Science:

• Geotechnical Engineering
• Soil Mechanics
• Computational Geomechanics

Background:

• Existing soil models struggle to accurately capture complex mechanical responses under over-consolidation and cyclic loading.
• Unified critical state models offer a framework for predicting soil behavior, but require refinement for diverse soil types.

Purpose of the Study:

• To present a modified unified critical state model, CASM-kII, for predicting the mechanical responses of clays and sands.
• To incorporate the subloading surface concept to describe plastic deformation and reverse plastic flow.
• To evaluate the model's performance under over-consolidation and cyclic loading conditions.

Main Methods:

• Numerical implementation of CASM-kII using a forward Euler scheme with automatic substepping and error control.
• Conducting a sensitivity study on three new model parameters.
• Comparing simulated results with experimental data for clays and sands.

Main Results:

• CASM-kII successfully captures plastic deformation within the yield surface and reverse plastic flow.
• The model demonstrates satisfactory prediction of soil mechanical responses under over-consolidation.
• Simulated results align well with experimental data for both clays and sands under cyclic loading.

Conclusions:

• CASM-kII provides a robust framework for modeling the mechanical behavior of both cohesive and granular soils.
• The model's ability to handle over-consolidation and cyclic loading enhances its applicability in geotechnical engineering.
• Further research can explore the model's performance with additional soil types and loading scenarios.