摘要: |
Pavement design is a process intended to find the most economical combination of layer thickness and material type for the pavement, taking into account the properties of the subgrade soil and the traffic to be carried during the service life of the road. The currently prevalent methods of pavement analysis and design, however, are more or less empirical in U.S. (AASHTO, 1993), which possess the shortcoming that the important type of pavement distress of rutting related to the accumulation of plastic or permanent deformations cannot be effectively considered. This project proposes an exploratory study on the application of the plasticity theory-based shakedown concept to the analysis and design of pavements under repeated loading, with a more realistic incorporation of the roughness impact of the top pavement layer on the dynamic amplification of vehicle loading as well as on the elastic stress responses in the underlying base course and subgrade soil.
The main innovations/objectives of this research include (a) a vehicle-road coupling model for estimating the additional dynamic vehicle load induced by pavement roughness considering time variant traveling speed; (b) development of a rigorous analytical solution for the elastic stress fields in asphalt-base-subsoil systems due to the moving surface loads determined above, which is essentially desirable for the subsequent shakedown limit analysis; and (c) proposition of a potential shakedown approach for perpetual flexible pavement design. The intended outcomes of this project will not only provide a theoretical framework for assessment of the stress responses in multilayered pavement systems with proper consideration of the vehicle speed, pavement roughness and thickness, etc., but also the shakedown analysis and design method that could prevent the flexible pavement system from excessive rutting, shall be of great practical value for prediction/design of the layer thickness that is required to warrant shakedown state of the pavements (i.e., no excessive rutting) in the long run. |