Finite Element Modeling of a Thawing Pavement Structure

Abstract

A material model for soft soil was developed to simulate the deformation behavior of a thawing soil under vehicle loading on paved and unpaved roads. Freeze–thaw action produces a loose, wet soil that deforms significantly under vehicle loads. The material
model represents a frost–susceptible fine sand, which was used in full-scale tests of paved and unpaved road sections in CRREL’s Frost Effects Research Facility (FERF). The material model was fine-tuned using triaxial test data and validated against direct shear test data. The material model was then used in a dynamic, three-dimensional finite element simulation of a paved road structure subjected to vehicle traffic by loading from a rolling wheel. This was used to understand the effects of thaw on the degradation of paved roads. These initial findings show that the pavement layer experiences maximum stress when the base layer is thawing. This supports observations that the majority of the rutting of a pavement system occurs during the thaw cycle.