Study on the Small-strain Behaviors of Unsaturated Soils

Non-linear stress-strain characteristics and strain dependency of stiffness of saturated soils at small strain level have been reported by many researchers. However, the non-linear stiffness of unsaturated soils is not fully studied. The aim of this study is to clarify main factors affecting the non-linear stiffness of unsaturated soil at small strain range for a precise prediction of various ground deformations. Experiments were conducted with both sand and cohesive soil, by using a triaxial apparatus developed for small strain measurement. As the important factors for mechanical behaviour of unsaturated soils under small strain range, the effects of suction and mean net stress, which introduce the decrease of void ratio and degree of saturation, were discussed in the study.