Centrifuge penetration tests in saturated layered sands

In principle, the penetration resistance of saturated sands should be a function of relative density, relative crushability, and relative speed of penetration. Excess pore pressures due to high penetration velocities should be measurable, and related to soil permeability, and therefore grain size. Piezocone tests (PCPT) have been carried out in centrifuge models to investigate the sensitivity to layering and grain size. Models consisted of fine silica sand sandwiched between two layers of coarse silica sand. A 12-mm diameter model piezocone was pushed into the models at different penetration rates to observe the effect of layering under different loading conditions and permeabilities of the sand layers. Additionally, a more viscous pore fluid was used in a second series of penetration tests to correct the centrifuge modelling of penetration process and flow of fluid within soil. The data are used to discuss the methodology of characteristic grain size interpretation and the use of viscous fluid in centrifuge tests.