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以沙漠公路风沙土路基为研究对象,通过室内风蚀风洞试验研究路基的风蚀破坏规律,以及路基不同断面对风沙流运动的影响。以路基高度、路基边坡坡率和路基宽度作为路基断面主要设计参数,研究不同路基断面下风沙流扰动、增速、减速、恢复的过程,以及路基周围风速流场的变化特征,分析路基病害较未病害时路基周围流场的变化。试验结果表明:路基高度和边坡坡率对风沙流运动的影响较大。随路基高度增加,路基对风沙流流场扰动增强,迎风坡坡顶处吹蚀破坏和背风坡坡底处堆蚀破坏越显著,在确定的路基边坡坡率下,路基模型高度为250mm较模型高度为60mm时,迎风坡坡顶风速增加1.13倍,背风坡坡底风速减小2.53倍,建议沙漠公路路基高度宜小于2.5m。进一步,在确定的路基高度下,比较不同的边坡坡率对路基沿程风速的影响,发现当路基边坡坡率为1:1.75时,路基沿程风速变化不明显,沙漠公路风沙土路基不宜被风蚀破坏。
The wind-blown sandy roadbed in desert highway is taken as the research object. The wind-induced wind tunnel test is used to study the wind erosion and failure rules of subgrade as well as the influence of different cross-sections on wind-blown sand flow. Taking the height of subgrade, the slope of subgrade slope and the width of subgrade as the main design parameters of subgrade section, the process of disturbance, growth, deceleration and recovery of wind-sand flow under different sections of subgrade are studied, and the variation characteristics of wind velocity and flow field around subgrade are analyzed. Changes of flow field around subgrade when no disease occurs. The test results show that the influence of subgrade height and slope gradient on the sand flow movement is significant. With the increase of embankment height, the subgrade disturbance to the flow field of wind-blown sand is enhanced, and the blowout destruction at the top of the windward slope and the heap erode at the bottom of the leeward slope are more significant. Under the determined slope of the subgrade slope, the subgrade model height is 250mm When the model height is 60mm, the wind speed at the windward slope increases by 1.13 times and the wind speed at the bottom of the leeward slope decreases by 2.53 times. It is suggested that the height of desert highway subgrade should be less than 2.5m. Furthermore, under different subgrade heights, the influence of different slope slopes on the wind speed along the embankment is compared. It is found that when the slope of subgrade slope is 1: 1.75, the change of wind speed along the subgrade is insignificant. Should not be destroyed by wind erosion.