Modeling and Numerical Analysis of Expansive Soil in Stress Path Tests

The study assesses the possible effects of stress path on expansive soil simulating the different loading path similar to what is expected in the field. The testing program concentrated on a series of consolidated-drained triaxial compression and extension tests of expansive soil specimens on 50 mm diameter and 100 mm high samples. Testing was carried out at consolidating pressures ranging between 0.10– 0.60 MPa using Geotechnical Digital System computer control triaxial apparatus. The Cam-Clay model parameters for expansive soil was determined based on isotropically consolidated drained shear test and consolidation test results. Computations were performed using the model constant and finite element CAD software SIGMA/W to predict the stress-strain response for different consolidation pressure and stress path tests. Predicted results were compared with measured response to assess the validity of the Cam-Clay model and finite element model parameters. The model prediction was found to yield acceptable results and is quite effective in demonstrating the effects of stress paths, effective stresses and strains of consolidated expansive soils.