ABSTRACT
Several CPTU tests were performed in both ideal and adverse conditions at a test site in Zwijnaarde. The influence of exposure to unsaturated soils was examined by holding well-saturated piezocones in dry sand for several minutes without a protective rubber membrane. After the exposure to dry sand, penetration was performed from the ground level through the unsaturated and saturated subsoil. These tests show suboptimal pore pressure measurements, compared to the tests under ideal circumstances, regardless of the duration of the exposure to dry sand. Results reveal that, in adverse conditions, the densely packed sandy top layer, rather than the exposure to dry sand, has contributed to the desaturation of the piezocones. The impact of the viscosity of the saturation liquid on pore pressure quality was studied by performing tests with a 50 and 100 cSt silicone oil. Under ideal circumstances, the viscosity does not play a role in terms of quality of the pore pressure measurements. However, in adverse conditions, results showed a better performance for a silicone oil with 100 cSt viscosity.
