Modeling of the Behavior of Expansive Soils

In the preliminary reconnaissance phase and once the swelling of soil is suspected, it is possible to obtain an estimation of swelling parameters (amplitude and pressure) using numerous rheological models proposed in the literature. These models relate the parameters of swelling to the geotechnical parameters determined from mechanical tests. The analysis of the behavior of clays is conducted by numerical simulation tests of compression and swelling by using the oedometer. This analysis is conducted using the software CASTEM2000 team from CEA-France. This simulation allows-among others-to develop a predictive procedure for estimating the parameters of swelling by the use of constitutive equations of Cam-Clay and Alonso. It should be noted that different simulations are performed; those using oedometer tests by the Cam- Clay model, and Alonso and free swell tests by the Alonso model. The results of this work show that the compressibility has been correctly simulated by both models. The phase of swelling has been simulated by the model of Alonso as the Cam-Clay model can simulate it. It should be noted that the Alonso model underestimates very fluffy swelling soils.