Experimental evaluation and theoretical analysis of multi-layered road cumulative deformation under dynamic loads

Excessive deformation of multi-layered road structure induced by vehicle traffic loading is one of the main reasons leading to pavement failure. In this paper, the elastic response and cumulative deformation of a multi-layered road structure under dynamic loads are investigated through experimental tests and theoretical analysis. First, a physical model with thin asphalt surfacing layer, cement stabilised gravel road base and layered decomposed granite soil subgrade is built to better understand the dynamic behaviour of a multi-layered road structure system. Experiments are performed to determine the elastic responses (vertical stress and displacement) and cumulative plastic deformation at different depths of road structures. A calculation method of the dynamic stiffness matrix is developed on the basis of an assembly process compatible with good numerical efficiency, and results from the calculations are verified using model experiment data. Then, the dynamic deviator stress is derived according to the dynamic stiffness matrix method and is used to formulate a cumulative deformation computational model considering both road infrastructure and its soft subsoil. Moreover, the cumulative deformation of a road on soft subsoil under repeated traffic load is analysed for different material properties of the road layers using the presented method.