Research On Dynamic Response Of Vehicle-pavement In The Bridge-subgrade Transition Section Base On Safety

The existence of differential settlement in bridge-subgrade transition section will reduce the running speed of the road, and also affect its safety and comfort properties directly. So it turns to be one of the key technical problems to affect the normal operation of the road. The thesis operates a systematic analysis on the differential settlement in bridge-subgrade transition section and its dynamic response, proposes a kind of differential settlement control criterion based on running safety, and also analysis the dynamic response of the pavement structure in bridge-subgrade transition section, and eventually we provide a theoretical basis for the timely maintenance and rational design of the bridge-subgrade transition section.The paper established a vertical vibration system combined with the feeling of human, the vehicles and the road, compiled MATLAB program, analyzed the dynamic response of 5-DOF vehicle model when going through the bridge-subgrade transition section, and eventually we gained the models' change laws influenced by running speed, load, setting height, the length of the approach slab,change in longitudinal slope, etc. we use dynamic load factor as evaluation index to evaluate the capability of the bridge-subgrade transition section to withstand the dynamic load, and also calculated the additional dynamic load and dynamic load factor when the vehicle running through the bridge-subgrade transition section. Based on the running safety of the bus, we proposed the differential settlement control criterion in bridge-subgrade transition section. In order to make a full consideration of the influence caused by the vehicles'dynamic loading and improve the structural design method of the bridge-subgrade transition section, We built a three-dimensional finite element model for the bridge-subgrade transition section, divided the loading into impact loading, analyzed the dynamic response of pavement structure, compared different response of pavement structure under dynamic and static load, introduced the modified dynamic load coefficient of deflection, tensile stress and compressive strain on the base surface for asphalt pavement on the basis of the result.