Studying the energy distribution of the dynamic influences of road transport on the layers of nonrigid pavements

The paper deals with studying the distribution of the scattered (dissipating) mechanical energy transferred to the pavement cover when it is used by road transport. For the numerical simulation of the energy transfer process we improved the analytical model of the dynamic stress-strain state of the multilayered half-space by introducing the moving coordinate system. The energy distribution was studied for three road structures with different strengths. For each structure we obtained the amplitude-time characteristics of stress and strain on the surface of the coating layers, on the base and subgrade soil which have been used to build the dynamic hysteresis loops. We analyzed the areas of the dynamic hysteresis loops on the surface of the coating layers as well as the base and subgrade soil, which made it possible to reveal the qualitative and quantitative dependences of the density distribution of energy dissipation in the pavement layers. It is found that when the solidity of the road structure increases, the energy density which is dissipated on its surface decreases. The rate of the energy attenuation of wave fields in road structures which has been generated by the impact of the design load vary significantly depending both on the solidity of the pavement and various types of its structural layers. In this case the greatest difference is determined by the material properties which are used as the base layer (reinforced, unreinforced). Based on the studies, a new approach of evaluating the design service life of nonrigid road structures in terms of the energy transferred on its surface during its entire service life has been proposed.