Research On The Relationship Between Pavement Evenness And Vehicle Dynamic Load

Under natural factors and vehicle loading, especially vehicles loadings, high-level highway pavement evenness will attenuate, i.e., pavement evenness will develop to a worse condition from a better condition, also i.e. pavement evenness become worse. As vehicle moves on roughness pavement, wheel will produce additional dynamic load to pavement, which will speed up deterioration of pavement evenness, and the deterioration will make wheel increase the additional dynamic load to pavement. Therefore, there is a couple function between pavement evenness and vehicle dynamic load.According to the actual measurement result of Xi—Bao highway pavement evenness, this project sets a unevenness model of pavement which imitate pavement surface by using sine curve, and sets a vehicle vibration model of four-degree of freedom by taking the medium-sized load truck as an example. On the base of above-mentioned models, the project analyzes left wheel and right one when vehicle wheels are not impelled at the same time suffered vehicle dynamic load when vehicles travel in a different speed on the different pavement model (wave length, amplitude are different); analyzes vehicle dynamic load's distribution along longitudinal route under different conditions. Discovering that dynamic load is in direct proportion to amplitude when wavelength is regular, the maximum dynamic load rapidly increases when pavement wavelength is close to the wavelength of vehicle automatic vibrating frequency. That left wheel and right one impelled not in the synchronism makes dynamic load coefficient increase under the common wave length condition but in the synchronism makes influence of resonance function more obvious when impelling angel frequency of pavement is equal to definite angel frequency of vehicle, producing greater dynamic load on the resonance. The analysis result of this research point out that vehicle traveling on the pavement produces probably very great dynamic load to the pavement. That maximum dynamic load coefficient may be over 2 shows maximum dynamic load is over 2 times to the vehicle dead load, at the same time maximum pressure which pavement is beard is 3 times to dead pressure of tyre. This has a big difference from the conception people accepted in a long time that dynamic load is 0.3 to 0.4 times to dead load (i.e. maximum pressure pavement beard is 1.3 to 1.4 times to dead pressure of tyre.) Based on the shell permanent deformation pre-appraisal theory, this paper calculates pavement's permanent deformation under the dynamic load, then analyzes the evenness variation of Xi—Bao highway K63-K72 pavement, and makes a contrast to the actual measure result. The analysis result points out, that the paper's analysis result has a fairly good consistent with the actual measure result, and show the paper's analysis to dynamic load and calculation to the pavement evenness variation are fairly reliable.The project firstly analyzes dynamic load of traveling vehicle by using a vehicle vibration model of four-degree of freedom considering vehicle roll factor, and makes analysis precision largely improve. Firstly setting a interrelation between pavement evenness, dynamic load and pavement evenness variation, and making a fairly satisfied prediction to the pavement evenness variation.The research achievements analyzes and grasps developing variation law of pavement evenness, then provide a certain theory basis for reasonable formulation of pavement maintenance management criterion and promptly implementation of maintenance management measure, and provide technical assistance for the appreciation of asphalt pavement using performance and maintenance, have fairly important theory value and certainly practical significance.