An Initial Study on the Viscous Behaviour of a Partially Saturated Kaolinite Clay Based on Triaxial Tests

Creep plays an important role in the estimation of long-term behaviour of cohesive soils. It is, among other parameters, related to the viscosity of the soil, hence rate-dependent. Apart from the degree of saturation and the initial void ratio, the stress rates as well as isotropic / deviatoric stress states determine the behaviour. A partially saturated kaolinite is selected as the test material. The creep tests are performed in a triaxial apparatus with tensiometer-measured suction. To combine the viscous and the elasto-plastic behaviour, a new triaxial apparatus performing deviatoric triaxial tests has recently been developed, which is described in detail in this paper. Selected results of the triaxial and creep tests are presented. The creep tests show good agreement with results from the literature and may be directly used to formulate an elasto-visco-plastic constitutive law for this type of soil.