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Inner Mongolia University (2018)

The Cause and Mechanical Analysis on the Transverse Uplift of Asphalt Concrete Pavement in Desert Area

张海龙;

Titre : The Cause and Mechanical Analysis on the Transverse Uplift of Asphalt Concrete Pavement in Desert Area

Auteur : 张海龙;

Grade : Master’s Theses 2018

Université : Inner Mongolia University

Résumé
The transverse uplift disease occurred on some highways in Ejin Banner,Alxa League which is located in desert area,with distribution discontinuous along its route and feature that is not easy to eradicate,shows characteristics different from other common road diseases,and seriously affects the road to perform its normal functions.To explore the disease cause and the mechanical response of the pavement structure influenced by the disease is provided with great practical significance and reference value for highway construction and disease prevention in this area.Through field investigation,sampling and indoor test analysis,the pavement uplift disease cause is explored.Based on the cause,the mechanics model of the pavement uplift disease entity is established by utilizing the relevant mechanics theory to analyze the internal stress and damage form of the pavement structure.After that,through using Abaqus,a finite element software,a simulation model of the pavement transverse uplift entity is established.The influences of pavement structure layer thickness and elastic modulus on the pavement structure stress at different salt expansion stages and its parameters sensitivity are analyzed.At last,in order to obtain the longitudinal pressure magnitude of the pavement structure caused by temperature,improve the pavement uplift mechanical model subjected to the thermal expansion action,and effectively predict the temperature field distribution of the pavement structure,a heat transfer model with one-dimensional unsteady layered pavement structure is established by utilizing the heat transfer theory.The main conclusions obtained as follows :(1)Through investigating the disease characteristic,environment and climate conditions in the area where the disease is occurred,sampling and analyzing the soil composition at different depths in disease section,combining the thermal expansion performance analysis of subgrade material based on correspondent experiments,it is illustrated that the pavement transverse uplift in Ejina area is mainly caused by the salt expansion action of the subgrade and the thermal expansion action of the base.(2)It can be known from the thermal expansion mechanical model of the pavement structure,when the pavement structure longitudinal pressure caused by temperature is higher than its buckling critical pressure,the pavement structure will be destroyed due to its instability.The pavement structure deflection formula is deduced from the salt expansion mechanical model.Through this formula,the maximum deflection that the pavement structure can withstand at elastic phase can be calculated.(3)From the finite element analysis of the disease entity structure,it can be seen that the pavement structure stress under the influence of salt expansion action is positively related to the magnitude of salt expansion force and distribution width of salt expansion area.The maximum pavement structure stress always appears in the center of the uplift area.The base stress is higher than the surface,and will be destroyed precede the surface.The influence of the base thickness on the pavement structure stress is obviously higher than the surface thickness,modulus and the base modulus.(4)A one-dimensional unsteady heat transfer model of layer pavement structure is established through utilizing the heat transfer theory.The distribution formula of pavement structure temperature field is derived to predict the temperature distribution inside the pavement structur

Mots clés : pavement transverse uplift; cause analysis; uplift mechanical model; finite element simulation; sensitivity analysis; temperature field distribution;

Présentation (CNKI)

Page publiée le 18 mai 2019