We discuss the numerical implementation of a creep constitutive model to facilitate
the modeling of long-term soil creep. Multidimensional soil creep models are
generalized from the one-dimensional soil creep model proposed by Bjerrum in 1967,
which was based on field test data and was later modified for transient loading
conditions by Vermeer et al. in 1998. Here this differential form of one-dimensional
creep model is extended to two- and three-dimensional states of stress and strain by
incorporating concepts from viscoplasticity. The devised multidimensional creep
model takes into account both volumetric and deviatoric creep strain, with creep
deformation of the soil defined by several material parameters. The model is
incorporated as a plane strain element subroutine in a nonlinear, time-incrementing
finite element program, along with iterative corrections within each time step.
Numerical analyses are conducted to demonstrate soil creep by using published
experimental data. The verified computer code will be a useful research
tool for estimating settlements in structures founded on soils exhibiting
creep.