Applicability of MCC and CASM-Based Structured Soil Models

In situ soils generally exhibit a structure due to bonding that exists between the soil constituents. The behaviour of the structured clay is different from the reconstituted clay which needs to be modelled accurately. This study aims to understand the accuracy and reliability of two different phenomenological models based on the critical state framework formulated to predict the behaviour of structured clay. These models (Lee and CASM-n) are calibrated with drained conventional triaxial experiments for two different percentages of cement content (high and low cement content) after obtaining the material parameters. A non-linear optimization technique is used to obtain other model-fitting parameters. After obtaining the parameters, a single-element explicit integration scheme is used to simulate the drained triaxial test for different confining pressures. The Lee model predictions deviate from the experimental results for the materials that exhibit a dominant frictional response, such as that exhibited by low-cemented clays, but predicted the behaviour of cohesion dominant response as observed for high-cemented clays reasonably well. However, CASM-n model was able to predict the behaviour of low-cemented clays accurately.