Abstract: Many parts of the continental US are underlain by expansive clays that undergo significant changes in volume (swelling or shrinkage) due to seasonal changes in moisture content. Existing methods for estimating these effects are based on simplified empirical procedures that are grossly overconservative. A new research project aims to develop more reliable methods of analysis by simulating strains of partially saturated clay due to seasonal changes in matric suction. The research will calibrate properties for a complex elastoplastic model (BExM developed at UPC, Barcelona) based on a program of laboratory tests on an expansive clay and to install a field station to monitor pore pressures and ground deformations at a test site in Texas.