Influence Of Subgrade Rebound Modulus On Asphalt Pavement Structure

Because of its superior performance,asphalt pavement is widely used in road engineering.However,due to various factors such as the construction process,compaction,and moisture content at the construction site,the uniformity of the modulus of the roadbed cannot be effectively guaranteed.In addition,the repeated effects of the vehicle load,the unevenness of the rebound modulus of the roadbed Will be more significant,seriously affecting the normal use of pavement structure.In view of this,the treatise uses the Huangshi Expressway to rebuild and expand the K284 + 240-K284 + 260 subgrade in the Gaocheng to Shijiazhuang section as the engineering background.Through the laboratory test and field test methods,the uneven distribution of the elastic modulus of the roadbed is studied.The three-dimensional finite element model of the subgrade rebound modulus is established based on the meta software,and the influence of the subgrade rebound modulus on the dynamic response of the asphalt pavement structure is studied.The main work of the thesis includes:(1)Analyze the influencing factors of the rebound modulus of the roadbed filler,and establish the relationship between the dynamic and static rebound modulus.On the basis of determining the basic physical properties of the roadbed filler in the test section,the bearing plate test and the dynamic triaxial test are performed.The influence of water content,compaction,confining pressure,deviator stress and spring modulus was studied,and the relationship between dynamic and static spring modulus was established.(2)The field load of California bearing ratio CBR was used to study the uneven distribution of roadbed modulus.In the analysis of the uneven distribution characteristics of the roadbed,the data consistency statistic value h between lanes and the data consistency statistic value k in the lane are used to quantitatively analyze and evaluate the unevenness of the roadbed modulus.(3)The finite element software Abaqus is used to establish the finite element model of the subgrade rebound modulus.In the modeling process,the cosine function is used to represent the wavy distribution state of the subgrade rebound modulus.The distribution state of the spring modulus under different conditions is written as the target subroutine and substituted into the finite element software to establish the subgrade rebound mode.3D finite element analysis model of asphalt pavement with varying volume.(4)The influence of the roadbed rebound modulus on the structure of asphalt pavement under moving load is analyzed.The dynamic response of asphalt pavement structure with different wavelengths,amplitudes and vehicle speed changes of subgrade rebound modulus is studied.Based on the research results,the standard recommended values for the control of uneven elastic modulus of asphalt subgrade at different design speeds are proposed.