Essential features of compacted silty sand behavior via suction-controlled triaxial testing

Abstract

The main intent of this work was to gain further insight into some of the limitations (and potential) of the Barcelona Basic Model (BBM) in predicting the stress-strain response of compacted unsaturated soils that are prone to post-peak strain-induced softening during suction-controlled shearing. To this aim, a comprehensive series of suction-controlled tests were conducted on statically compacted specimens of silty sand using a recently implemented, servo/suction-controlled, double-walled triaxial apparatus. The brittle and dilatant nature of the test soil, as expected, did not allow for good agreement between the experimental and BBM predicted stress-strain responses of compacted silty sand, since post-peak softening was not adequately captured. BBM simulations, however, held reasonably good during the early shearing stage (up to about 1-2% total shear strain), and at higher values of shear strain, that is, close to critical state condition.