Theoretical and experimental investigations on the role of transient effects in the water retention behaviour of unsaturated granular soils

Abstract In the present study, an experimental setup is presented and employed to examine the influence of rate of change of saturation on the transient water retention curves of granular soils with a low suction range. The results are evaluated and compared to existing theoretical approaches to model the non-equilibrium soil–water retention behaviour as well as to experimental findings from other researchers. Furthermore, suction stress characteristic curves under non-equilibrium conditions are obtained. Finally, the importance and the application of the results in hydro-mechanical modelling of unsaturated soils are discussed.