Experimental investigations and field observations of post-construction deformations of geo-structures such as roads, railways, and dams have proven the dependency of the mechanical response of soft soils to the time and rate effects. Soft soils typically present a tendency to undergo continuous compression with time (creep), even after excess pore pressures have substantially dissipated. Furthermore, these time-dependent deformations typically occur under changing climatic conditions including seasonal rainfalls, flooding, and droughts which can result in translation of the soil state from saturated to unsaturated states and vice versa. Such state variations in progressively creeping soft soil foundations can significantly influence the serviceability of shallow-depth geo-structures. A thorough understanding of such translational effects on the creep response of soft soils is therefore essential for development of hazard prevention strategies and modelling viscous response of soft soils. This study presents an investigation of the viscous response of a clay soil, namely London clay, under saturated and unsaturated conditions. Long-term (30 days) one-dimensional (1D) creep tests were first carried out on saturated clay samples, subjected to different vertical stress levels, by means of a modified oedometer cell equipped with in-house made high-capacity tensiometers for monitoring pore-water pressures both in positive and negative range during the experiments. 1D creep tests on clay samples prepared at different initial degrees of saturation were then carried out under the same loading conditions. The obtained results helped in development of an insight into the soft soils’ viscous response under unsaturated conditions.
|Publication status||Published - 2017|