UC San Diego

A triaxial cell was developed to investigate the shear strength of unsaturated silt under elevated temperatures and high suction magnitudes. The results from a series of drained triaxial compression tests on compacted silt specimens are presented in this paper. After anisotropic compression, some specimens were heated before suction was applied, while others were heated after the application of suction. The shear stress–strain curves of the soils under high suction magnitudes showed a brittle failure mechanism, with a clear increase in peak shear strength with net confining stress. Heating after suction application led to a greater peak shear strength than reference tests at ambient temperature, whereas heating before suction application led to a lower peak shear strength. Despite the observed path effects, a single peak failure envelope was defined when evaluating the data in terms of effective stress. The suction stress concept was used to define the effective stress, and the values of suction stress were found to be linked with a non-isothermal definition of the soil-water retention curve.