Research And Numerical Analysis Of Typical Structure Of Asphalt Pavement In Yulin Aeolian Sand Area

Yulin is located on the edge of the Maowusu Desert,the aeolian sands are widely distributed here.In recent years,with the rapid development of socio-economic,highway construction in desert areas continues to be pushed forward.However,the road construction materials are scarce in desert areas,Lime soil,sand and other materials used in traditional road construction need to be transported over long distances,and the construction cost is high.Therefore,used as road-building materials,aeolian sands can not only solve the shortage of road-building materials,but also achieve sustainable development in the region,with significant economic benefits.Based on the reconstruction and expansion project of Shanmeng section of the National Highway 210 and Yujing section of the Provincial Road in Yulin,Shaanxi Province,this article studies and numerically analyzes the typical pavement structure and propose a standardized plan in yulin aeolian sand areas by using aeolian sand as roadbed and base materials.This paper studied and analyzed microstructure characteristics and particle composition,proposed the 0.15 mm key sieve hole,and finally classified the aeolian sand in Yulin area:0.15 mm pass rate less than 30% is class A,Class B is between 30% and 60%,and class C is over 60%.The experiment researched the cement(fly ash)stabilization technology of aeolian sands,determined the mix ratio and material parameters,and provided basic data for pavement structure design and check calculation analysis.Investigated and analyzed the existing traffic volume in Yulin,and classified the traffic load level,then based on the highway level and traffic load level,different types of asphalt pavement structures were proposed.According to the theory of the elastic layered system and the American AASHTO design method,the proposed pavement structures were checked and analyzed,and the thickness of each layer was determined.Finally,the typical asphalt pavement structures were recommended,and socio-economic benefits were analyzed.The results show that:(1)Aeolian sands have good technical performance,and can be used as the construction materials of roadbed and road surface by comprehensive stabilization technology where lime and gravel are scarce.(2)The expressway and the first-grade highway are divided into extremely heavy,extra-heavy and heavy traffic load classes;The secondary highway is divided into extra-heavy,heavy and medium traffic load classes;The third and fourth grade highways are divided into heavy,medium and light traffic load grades.(3)Through the calculation and analysis of the pavement structure,the stable aeolian sand base asphalt pavement can fully meet the requirements of the technical specifications,but the thickness is slightly changed from the recommended value.(4)Compared with the design method of China,the thickness of the asphalt surface layer calculated by the American AASHTO method is slightly smaller,while the thicknesses of the base and subbase are almost unchanged.(5)The typical structure of asphalt pavement is recommended and its socio-economic benefits are analyzed.It is found that the use of aeolian sand as a building material of roadbed and pavement base can save the construction cost and have the social benefits of environmental protection and sustainable development.