Bearing capacity of unpaved roads

Elastic layer theories may be valid for relatively stiff pavement materials and pavements subjected to low traffic stresses; however, the assumption of linear elastic behavior is not suitable for thin pavements and unpaved roads consisting of untreated granular bases over cohesive subgrades. The behavior of such pavements, even al low traffic stresses, is markedly nonlinear. Pavement design methods based on a bearing capacity theory are more applicable to roads with thin pavements, This paper outlines an ultimate strength method of designing low-volume roads. A procedure for determining the ultimate loads in layered systems, incorporating the effect of matric suction, is also presented. Existing empirical relationships that account for traffic loading are utilized in the proposed design procedure.