Study Of Treatment Techniques For Highway Subgrade Base On Puddle Sections In Hetao Area

Deserts are widely distributed in Inner Mongolia. With the construction of large numberhigh grade highways, road construction materials have become increasingly obvious issues,and there are problems of poor foundation as well, such as perennial or seasonal puddles andsaline soil. Researches on road performance of aeolian sand and treatment techniques of poorhighway foundation are extensive and intensive, but there are few studies about highwaysubgrade base treatment on puddle sections by using aeolian sand. Though this treatmenttechnique has been applied in engineering before, there is a lack of theoretical analysis andtechnical guidelines. This paper relies on the project of provincial highway212from Wuyuanto Liushao and does a systematic study of subgrade base treatment techniques on low-lyingand puddle sections, which provides a theoretical support to base treatment using aeoliansand and broadens the application way of aeolian sand. Besides, this research will have agreat significance to the highway construction and sand damage control in Inner Mongolia.Firstly, this paper studies the property of aeolian sand in Inner Mongolia and treatmenttechniques of puddle sections, summarizes the physical, chemical and mechanical propertiesof aeolian sand by referring to a large number of articles and test data of the relying project.According to the investigation of low-lying and puddle sections along the project, this paperanalyzes the feasibility of using aeolian sand to deal with poor subgrade base and proposesthree treatment techniques——crushed stone slag cushion，aeolian sand cushion and aeoliansand cushion with a layer of geocell——on the basis of the original one.Secondly, using ABAQUS software to establish aeolian sand subgrade finite elementmodel, and then get the influence law of replacement thickness, structural parameters ofembankment height, slope ratio and hemming soil thicknes, and mechanical parameters ofaeolian sand, foundation soil and hemming soil on subgrade stability and deformation. In thisway, the suitable structural systems of aeolian sand subgrade on puddle sections in Hetao areaare recommended. For three test road sections, the settlement of subgrade is calculated andthe slope stability is analyzed, so that there can be a comprehensive comparison of theirtreatment effects and the feasibility of using aeolian sand to deal with subgrade base on puddle sections can be verified theoretically.Finally, this paper conducts a technical summary of the construction technology andquality control of these three treatment techniques combining with the construction andinspection data of the project, analyzes and evaluates the law of subgrade settlement of threetest sections using the layered settlement data of aeolian sand subgrade which are obtained byburing settlement plates and continuously observation. The results show that the subgradesettlement after construction of the treated sections satisfies the corresponding specificationsand these three treatment techniques have good treatment effects.