Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Sensors (Basel). 2022 May 24;22(11):3988. doi: 10.3390/s22113988.
Bridges and subgrades are the main route forms for expressways. The ideal form for passing through sandy areas remains unclear. This study aims to understand the differences in the influence of expressway bridges and subgrades on the near-surface blown sand environment and movement laws, such as the difference in wind speed and profile around the bridge and subgrade, the difference in wind flow-field characteristics, and the difference in sand transport rate, to provide a scientific basis for the selection of expressway route forms in sandy areas. Therefore, a wind tunnel test was carried out by making models of a highway bridge and subgrade and comparing the environmental effects of wind sand on them. The disturbance in the bridge to near-surface blown sand activities was less than that of the subgrade. The variation ranges of the wind speed of the bridge and its upwind and downwind directions were lower than those of the subgrade. However, the required distance to recover the wind speed downwind of the bridge was greater than that of the subgrade, resulting in the sand transport rate of the bridge being lower than that of the subgrade. The variation in the wind field of the subgrade was more drastic than that of the bridge, but the required distance to recover the wind field downwind of the bridge was greater than that of the subgrade. In the wind speed-weakening area upwind, the wind speed-weakening range and intensity of the bridge were smaller than those of the subgrade. In the wind speed-increasing area on the top of the model, the wind speed-increasing range and intensity of the bridge were smaller than those of the subgrade. In the wind-speed-weakening area downwind, the wind speed weakening range of the bridge was greater than that of the subgrade, and the wind speed-weakening intensity was smaller than that of the subgrade. This investigation has theoretical and practical significance for the selection of expressway route forms in sandy areas.
桥基是高速公路的主要路线形式。理想的通过沙区的形式仍不清楚。本研究旨在了解高速公路桥梁和路基对近地表风沙环境和运动规律的影响差异，如桥梁和路基周围风速和轮廓的差异、风流场特征的差异以及输沙率的差异，为沙区高速公路路线形式的选择提供科学依据。因此，通过制作公路桥梁和路基模型，并对它们的风沙环境效应进行对比风洞试验。桥梁对近地表风沙活动的干扰小于路基。桥梁及其迎风和背风方向的风速变化范围低于路基。然而，恢复桥下风速所需的距离大于路基，导致桥梁的输沙率低于路基。路基的风场变化比桥梁更为剧烈，但恢复桥下风场所需的距离大于路基。在风速减弱区的迎风面，桥梁的风速减弱范围和强度小于路基。在模型顶部的风速增加区，桥梁的风速增加范围和强度小于路基。在风速减弱区的下风面，桥梁的风速减弱范围大于路基，风速减弱强度小于路基。本研究对沙区高速公路路线形式的选择具有理论和实际意义。
