Effect of Soil Permeability on CPTu Test Results in Structured Clay Soils

Abstract

The PFEM implementation of fully coupled equations governing the solid skeleton deformations and pore fluid flow in porous saturated media is used to investigate the effects of soil permeability on cone tip resistance and excess pore pressure measurements in CPTu tests performed in a structured soil deposit. In the simulations, soil behavior is modeled with the FD_Milan model, a finite deformation version of the isotropic hardening model for structured soil originally developed at the Politecnico of Milano by Nova and coworkers. The results indicate that as soil permeability increases, the volumetric deformations around the cone tip become non negligible and the excess pore pressure in correspondence of the cone probes is also affected. The destructuration process caused by the intense deformations around the cone tip and along the shaft is responsible for a significant reduction of the expected net cone resistance based on the apparent value of the soil undrained strength.