Cyclic consolidation of soft soils

Cyclic consolidation of soils takes place during a multitude of geotechnical applications: besides vehicle and traffic loads, cyclic loading also plays an important role for pile driving processes and the dimensioning of foundations, e.g. for offshore windcraft plants. Particularly for soft soils these time-dependent consolidation processes are highly non-linear and therefore require a distinct analysis of the overlying mechanisms. In the present study the evolution of excess pore-water pressure dissipation during the cyclic consolidation process of Spergau Kaolin clay under haversine loading is evaluated on the basis of an existing analytical solution by Razouki et al. (2013) and an experimental study carried out at Ruhr-Universität Bochum using a newly designed oedometer device. A comparison of the results of the two analysis methods reveals that for both approaches the excess pore-water pressure dissipation during the cyclic consolidation process evolutes qualitatively similarly and frequency-independent. Due to the linear elastic material behavior assumed in the analytical solution however this approach is not capable of reproducing several effects caused by the non-linear material behavior of clay during consolidation, which can be captured by the experiments.