Rapid penetration of piezocones in sand

This study investigates the change in penetration resistance across different drainage regimes in sand using centrifuge piezocone tests. The model piezocone was jacked at various penetration rates into saturated loose and dense silica sand at gravitational acceleration of 50g. In order to achieve a wider drainage regime, the sand was saturated using both water and a viscous pore fluid (methocel cellulose ether with viscosity 715 times higher than water). The results indicate the net cone resistance increases with increasing non-dimensional velocity in dense sand, but reduces with increasing non-dimensional velocity in loose sand. This rate dependency in sand can be captured using a simple harmonic backbone curve.