Research Of Vehicle Dynamic Load And Pavement Mechanical Response

In existing asphalt pavement structure design theory, the thickness of each pavement structure layers is designed by using static load theory. This method is widely appropriate for the lower speed and smaller car. However, with the rapid development of the automotive industry the speed of vehicle is much faster and the weight of vehicle is much heavier, so researching on the dynamic load of vehicles and the dynamic response of the pavement has important theoretical significance and potential application prospects. Basing on the summary of the pavement structure design method, the vehicle dynamic load and the mechanical response of asphalt pavement, the influence of the roughness of pavement on the vehicle dynamic load was been analyzed, and the coefficient of dynamic load and the dynamic response of the pavement were been researched under the different of temperature and three types of the accumulation of axial load. The mechanism of rutting, deflection, cracks in the different conditions and the dynamic load coefficient were studied. The results of the study can provide theory and design basis for pavement structure design. The main research work are summarized from the following several aspects:(1) Considering the effect of road roughness on the road dynamic load, the time-domain model of road roughness was established. The results show that the dynamic load and the coefficient of dynamic load increase with the decreasing of pavement level when vehicles move at the same velocity; the dynamic load and the coefficient of dynamic load increase with the increasing of vehicle velocity when vehicles move on the road of the same pavement level.(2) Based on the multi-layer elastic layered system, asphalt pavement structure is divided into the top layer, the middle layer, the bottom layer, semi-rigid base and soil base. The3D finite element model was established by using the finite element software ABAQUS. The dynamic response of the pavement was studied at different temperature. The numerical results show that the pavement deflection, the maximum tensile stress of the bottom asphalt layer and semi-rigid base, the maximum compressive strain of the soil base top increase when the environment temperature increases. The pavement deflection and the maximum tensile stress of bottom asphalt layer are rapidly increase. So the environment temperature is an important factor in the pavement design. The movement of vehicle could cause the large pavement deflection and tensile stress of the bottom asphalt layer at high temperature, so the pavement life would decrease.(3) By calculating the rutting of pavement under the condition of the cumulative axle load contained50,100and150thousand times, the permanent deformation model of each structure layers of road is similar, the maximum subsidence deformation appears at the wheel tracks. However, the rutting of the different pavement layers is different because materials of the middle layer and the bottom layer are different, The rutting of the middle layer has larger fraction of the total rutting. The rutting of pavement is mainly produced by the deformation of middle layer, which is consistent with experimental observations. With the numbers of cumulative load increasing, the rutting of the road structure layers increase.