Suction-controlled triaxial tests have been used extensively to characterize unsaturated soils. However, this type of tests requires sophisticated and therefore expensive equipment and is very time-consuming. These limitations have been the main obstacles for research, dissemination, and implementation of unsaturated soil mechanics in engineering practice. Compared with the suction-controlled triaxial test apparatus, an oedometer for saturated soils is much simpler. It is 300 to 400 times more efficient to run a constant water content oedometer test for unsaturated soils than a suction-control...
