Research On Mechanical Response Of Long-uphill Asphalt Pavement Under Vehicle Dynamic Load

Longitudinal slope section of asphalt pavement under vehicle loads is susceptible todisease and damage. With the rapid development of highway traffic to the western hills andmountains, there are many longitudinal slope section of asphalt pavement. At the same timethe overload vehicles，the ambient temperature, the design method of the asphalt pavementand the construction technology of asphalt concrete pavement and other factors lead to thefact that the mechanical behavior of the asphalt pavement on large longitudinal slope is verycomplex. This paper is about the research of heavy vehicles under the action of thelongitudinal slope of the mechanical behavior of asphalt pavement.A serial analysis models were established to study the vehicle dynamic load of long andsteep slope asphalt pavement based on vehicle dynamic. A2-axle vehicle model to analysisdynamic load was established base on vehicle Parameters and pavement condition survey. Thedynamic horizontal force and vertical force of the2-axle vehicle were simulated withMATLAB. The influences of the slope, slope length, vehicle load and speed wereinvestigated.The FEA model of asphalt pavement with vehicle loads on large longitudinal slope wasestablished based on the elastic constitutive relation. To research the difference of mechanicalresponse between the visco-elastic and elastic asphalt road model，a three-dimensionaltransient finite element model of asphalt pavements with moving loads on large longitudinalslope was establishedbased on the viscoelastic constitutive relation. Through selectingmechanical response index, the distribution laws of mechanical response on two kinds of roadmodels were analyzed and studied. Through the analysis of the two road models, theinfluences of the slope, ambient temperature, vehicle load, pavement thickness and moduli onthe mechanical property indexes are studied.In order to detect he dynamic strain of asphalt pavement, a novel three-direction dynamicstrain sensor was developed. Using ABAQUS, finite element model of asphalt pavement withthe sensor was established to analysis the influences of the existence of sensor on the strainfield of pavement. The situ test on dynamic response of asphalt pavement on largelongitudinal was conducted using this sensor. By analyzing the test data has being analyzed， the laws of the influences of the slope length and vehicle load on dynamic response wereobtained. Through comparing difference of mechanical response between the test data and thesimulation results based on visco-elastic model and elastic model, it has been found that thesimulation result based on visco-elastic model was in good with test results and thevisco-elastic model can simulate well the structure behavior of asphalt pavement on largelongitudinal slope.The shear strength test of asphalt pavement on large longitudinal slope section wasperformed, because the shear stress between layers was one of the main reason which makethe semi-rigid asphalt pavement damage. A shear strength measuring instrument betweenlayers of asphalt pavement was developed, which can implement vertical loading. Througthindoor experiment, the shear strength test data no vertical loads is revised and the pavementlayer’s shear strength under different overload was obtained. The reliabiliy analysis of shearstrength was peformed. The shear stress between layers of asphalt pavement was analyzedunder different working condition by using the viscoelastic rheological model. The shearstress obtained from FEA were compared to the shear strength from the same workingcondition and the shear resistance of asphalt pavement on large longitudinal slope underdifferent reliabiliy was received.