Proposition of a Design Methodology for Unsurfaced Gravel Roads' Layers Based on the Concepts of Elasticity Theory, Soil Mechanics and Pavement Mechanics

This paper proposes a methodology for the structural design of unsurfaced gravel roads' layers, which was conceived with basis on the concepts of Elasticity Theory, Soil Mechanics and Pavement Mechanics. The methodology includes the definition of the thickness of the wearing course layers, when necessary, to withstand the vertical loads so as to not occur shear failure of one or more layers of the pavement and to minimize rutting. Furthermore, the ability of the surface layer to withstand horizontal stresses is also discussed. The proposal has the characteristic of being of a non-empirical nature, but requiring as experimental parameters only the cohesion and angle of friction of the layers, which can be obtained from triaxial or direct shear tests or, in a more simplified way, from unconfined compression and splitting tensile tests.