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基于Fluent气固两相流,运用k?ε湍流模型,对风沙环境下沙漠路基的风蚀破坏规律进行数值模拟研究。分析路基不同横断面下风沙流扰动、增速、减速、恢复的过程,以及路基障碍物的存在对风沙流扰动后造成的风速减弱区和恢复区,总结路基坡面特征点的风速变化规律,与现场实测结果作比较,二者具有很好的一致性。研究结果表明,不同路基横断面下风速减弱区和恢复区的分布对路基高度变化敏感,受边坡坡率的影响较小,不同路基高度、不同边坡坡率下路基沿程风速变化明显不同。边坡坡率一定,随路基高度的增加,路基周围流场扰动被增强,迎风坡坡顶风速增大显著,背风坡坡底风速下降愈明显;路基高度一定时,边坡坡率越小,路基沿程风速变化越平缓。当边坡坡率为1:3时,路基模型高度由1m增加到3m时,迎风坡坡顶风速增加12%,背风坡坡底风速降低约80%。建议为避免沙漠路基的风蚀破坏,路基高度不宜太大,边坡坡率较小为宜。
Based on the Fluent gas-solid two-phase flow, the k? Ε turbulence model is used to simulate the wind erosion of the desert subgrade under wind-blown environment. This paper analyzes the process of disturbance, growth, deceleration and recovery of wind-sand flow under different cross-sections of subgrade as well as the wind speed reduction and recovery areas caused by the presence of roadbed obstructions, summarizes the wind speed variation of the characteristic points on the subgrade and Field measurements for comparison, the two have a good consistency. The results show that the distribution of wind speed reduction zone and recovery zone is sensitive to the change of subgrade height under different cross sections of subgrade, and is less affected by the slope gradient. The wind speed changes obviously along different subgrade levels and different subgrade slope rates . With the increase of embankment height, the disturbance of flow field around the roadbed is enhanced, the wind speed at the windward slope increases significantly, and the wind speed at the bottom of leeward slope decreases more obviously. When the height of roadbed is fixed, the slope slope is smaller, Subgrade along the wind speed changes more smoothly. When the slope gradient is 1: 3, the wind speed at the windward slope increases by 12% and the wind speed at the bottom of the leeward slope decreases about 80% when the height of the subgrade model increases from 1m to 3m. It is suggested that in order to avoid the wind erosion of desert subgrade, the height of subgrade should not be too big, and the slope slope should be smaller.