ABSTRACT
At present, Controlled Suction Tests with Simple Stress Paths (CSTs/SSP) are commonly used to characterize unsaturated soil behavior and develop constitutive models for unsaturated soils. This kind of tests several disadvantages: it requires advanced laboratory equipment, usually laborious, time-consuming due to lengthy equilibrium time. It is not uncommon for a simple isotopic CST/SSP usually takes several weeks or months. In addition, each CST/SSP can only provide limited information and is unable to capture the coupled behavior of the soil. Due to the lengthy testing process, sometimes the test results, especially for the water content change, are not reliable or simply not available. As a result, CSTs/SSP cannot be justified for routine engineering purpose and significantly limited the application of unsaturated soil mechanics in engineering practice. This paper discusses use of results from undrained tests for the constitutive modeling of unsaturated soils.
