Abstract
Two instrumented embankments built on a double-porosity landfill of clayey lumps were monitored in situ and modelled in a centrifuge. The field measurements showed high compressibility of the landfill.
Introductory modelling in a mini-centrifuge and oedometer testing demonstrated irreversible deformation at low stress ranges, and reversible deformation (swelling) at higher stresses, similarly to the behaviour of reconstituted material. Dry filling followed by saturation was recommended with respect to further development of the landfills in future.
The geotechnical centrifuge models confirmed that permeability was controlled by the complex structure of the clayfills. There were significant initial settlements on loading due to compression of open macro voids.
The double porosity structure in the fresh fill allowed excess pore pressures to dissipate quickly. Thereafter, dissipation was controlled by the permeability of the intragranular pores in the clay, once the intergranular pores had closed.