This study deals with the behavior of composite blends constituted of rigid and impervious grainsincluded in saturated clay paste of kaolin, considered as permeable and deformable. Permeabilitytests performed during standard oedometr tests (before each load step) highlight the key role ofthe original and actual state of the clay paste, and show the existence of a threshold of sandgrain concentration above which a structuring effect influences its permeability. In the light ofthese experiments some usual homogenization methods (with simplifying assumptions to make theproblem manageable) are considered in order to model the mixture permeability. Qualitative andquantitative comparisons with experimental data point out their respective domain of interest andlimitations of such approaches.

The paper presents a static load test of a pile with the largest vertical load in Poland to-date up to the force of 23000 kN. The test was performed in the centre of Warsaw on the construction site of a future high-rise building to be the tallest building in European Union. The designed building height measured from the ground level is 310 meters including an 80-metre mast. The foundation of the building was designed as a Combined Piled Raft Foundation (CPRF) utilising the barrettes and diaphragm walls technology. The test was carried out on barrettes with lengths of approx. 28 and 34 m and was aimed to estimate the stiffness (load-settlement relation) of the designed 17.5 metre-long barrette situated below the foundation level. In addition to that a series of extensometric sensors was placed inside the barrette to determine the distribution of the axial force.