Analysis of pavement response to subsurface deformations

The paper deals with modeling the response of pavement systems to subsurface deformations. An analytic formulation is developed in the context of layered elastic theory wherein the bottom boundary is distorted in a prescribed manner – forcing the medium to deform. In the basic case considered, an axisymmetric displacement field is imposed, consisting of vertical and radial components. A version of the model, dealing with a single elastic layer deformed only in the vertical direction (with frictionless bottom), is parametrically interrogated to study the influence of layer thickness and modulus on the resulting surface profile and vertical contact stresses. Furthermore, it is shown that by spatially superposing several axisymmetric solutions, general displacement shapes can be reproduced and analyzed. Such a scheme is demonstrated in an inverse type of analysis to a case study dealing with a sagging runway; using measured surface elevations, an attempt is made to backcalculate subsurface deformations and stress changes at the bottom interface of the structure.