Abstract: Piezo cone penetration tests(CPTU) on structured soils at different installation rates were carried out.Based on the masonry model proposed by SHEN Zhu-jiang,a viscous-elastic-plastic model for structured clays was proposed by adopting the overstress theory.It was assumed that the total viscous deformation was composed of sliding viscous deformation and damage viscous deformation.On the basis of nonlinear continuum mechanics,the total Lagrange method was used to develop an FEM consolidation analysis program for large-strain analysis.The CPTU tests were successfully simulated by the FEM program and the constitutive model.The parameter q0 was derived from the CPTU simulations with inversion method.