The Dynamic Responses Analysis Of Asphalt Pavement Structure With Pipeline Under Vehicle Load

Increasingly developed underground pipelines have become the new characteristics of municipal road construction The pavement structure with pipeline is difficult to compact which has been a main reason that made pavement damage.The first thing researching the pavement damage with pipeline under vehicle load is to analysis mechanical response of asphalt structure.In the traditional mechanical analysis of pavement structure,vehicle load is assumed to be dot uniform static loads which cannot simulate its characteristics of non-uniform and movement.Firstly,based on the result of practicle measurement of vehicles axis,the equivalent conversion was used to experess vehicle load,establishing a non-uniform and moving vertical load in the form of digital model;based on elastic system theory,establishing a3-D layered finite element model of asphalt road structure with the effect of vehicle load.Then,determined the factors which can affect the dynamic responses of pavemrnt structure,the numerical solution method of dynamic finite element model,the border conditions and material parameters,discussed the simplification and loading method of the vehicle load.Secondly,research the variation regularity of stress and strain of each layer structure in diffirent directions,including vertical,horizontal,vertical and vertical plane,which come to a conclusion that the maximum compressive stress of surface layer,the maximum compressive strain of subgrade,the maximum tensile strain,the subbase layer bottom of maximum shear stress are the most influencing mechanical indexes of asphalt pavement structure.Moreover,contrast the mechanics response of static load and dynamic load,the condition buried pipe and no-buried-pipe conditions.Finally,finite element models of different working condictions are established and controlling variables method are used to analyze change law of the mechanical response indicators of diverse affecting effects under the vehicle load.Results showed that,local stiffness of pavement structure with pipeline is changedand it is limited.The analysis of traditional static force cannot reflect the volatility and the positive-negative action of dynamic response of the pavement structure.The internal of asphalt surface layers have complicated horizontal strain for pulled,and pressure strain.Under the asphalt surface layer,shear stress and cut strain concentrated are appeared.The non-uniform and movement should be concerned in pavement mechanical analysis.The deep of buried deep,the modulus of backfill soil,the speed of vehcile and the the size of pipeline all have different influence on the dynamic responses.Therefore,it is important to master these laws and they must be usful in some extent in design and construction.