Development of Analytic Method for Computing Expansive Soil–Induced Stresses in Highway Pavement

Abstract

Highway pavements with longitudinal cracks are often seen on expansive subgrade soil. This paper proposes a model using the Winkler foundation theory to analyze the pavement by considering it as a beam resting on expansive soil. To integrate the heave/shrinkage of expansive soil in the model, the concept of virtual load is introduced by expressing it as a Fourier series. The virtual load is formulated following the inverse theory of mathematics by taking the Fourier constants as material parameters from the beam deflection equivalent to the heave/shrinkage of expansive subgrade soils. As an example of the model application, a case study was performed by incorporating the measured field moisture contents from research Roadway FM 2 in Texas. The extreme heave or shrinkage displacement of the expansive subgrade soil was estimated from the calculated moisture contents, which were obtained using software VADOSE/W. Locations of the cracks observed in the field matched well with the locations where the maximum bending moments were discovered from the established model.