The Experimental Research And Numerical Simulation Of Response Between Subgrade Of Highway And Wind Sand Flow In Single Orthogonal Wind Conditions

With the gradual expansion of human practice to the desert and Gobi,wind and sand disasters have gradually become one of the most urgent problems to be solved in the construction and operation of the project.This article is based on this: firstly,model test and finite element simulation are used to study the changes of the wind sand flow structure through the subgrade;secondly,according to the characteristics of wind sand flow structure,the influence of different height of wind sand flow on Subgrade sediment accumulation is studied;thirdly,the Fluent software was used to simulate the change of flow field when the wind sand flowed through the road base and the sediment morphology near the roadbed was studied.In this paper,the process of the test device is first constructed.According to the characteristics of the air flow in the test process,the test section and auxiliary test section of the sandbox structure were divided,and the flow field in different locations of the sandbox was calibrated.At the same time,the water content of sand particles,air humidity and so on are calibrated.Then,taking wind sand flow structure under the condition of flat sand bed,whether wind speed profile,vertical distribution of grain size and vertical distribution of sediment volume before and after subgrade and roadbed are taken as the breakthrough point.The following problems are studied when the wind sand flows through the road base: What changes will happen near the roadbed when the roadbed is subgrade? What kind of variation will the wind speed profile produce? What are the effects of the roadbed on the particle size distribution and the sediment discharge? Next,the wind sand flow structure under experimental conditions is obtained and the structure of wind sand flow is decomposed according to different heights,wind speeds and particle diameters to influence the subgrade by the wind sand flow structure of different parts or different heights in different wind speeds.The sediment volume in a certain range of distance from the subgrade is selected as the research object and the sand accumulation of different height of wind sand flow structure in a certain range on both sides of the subgrade is analyzed under different wind speed conditions.The proportion of sediment volume in different range of subgrade to the influence degree of subgrade is defined and discuss the influence of the inlet velocity,sand outlet height and percentage of medium sized grains of sand by grey correlation theory.Last,considering that the fluid flow process is very complex,it is not easy to observe the motion state of the wind sand flow in the laboratory.So,the Fluent numerical analysis software is used to simulate the movement patterns and changes of the fluid field when the wind sand flows through the road base,and the influence of the inlet wind speed on the sand flow field near the roadbed is discussed,and the source of sand particles near the roadbed and the distribution pattern of sand and sediment accumulation within a certain range of the subgrade are discussed.On the basis of the above research,some corresponding conclusions are drawn: When the wind sand flow structure passes through the roadbed,the sand flow structure on the side of the windward side and the lee side of the roadbed will change obviously.There is a certain relationship between the wind speed profile and the inlet wind speed.The sand concentration and velocity at different heights are related to the sand accumulation in different areas of the subgrade.The influence of sediment load,inlet wind speed and middle sand ratio on the sand accumulation of subgrade is different.When sand grains move in the airstream,they will be affected by various forces,which will lead to different sources of sand from different parts of the roadbed.The accumulation process of sand near the roadbed is closely related to air velocity and atmospheric pressure.