Characteristic Differences of Wind-Blown Sand Flow Field of Expressway Bridge and Subgrade and Their Implications on Expressway Design

Abstract

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.

Review of Sensor-Based Subgrade Distress Identifications

“…Detecting road distresses holds the potential to improve the service performance of the subgrade, prolong the service life of the road, and curtail associated costs. Over time, as roads undergo extended periods of use, a plethora of defects may manifest within the subgrade, encompassing embankment and subgrade irregularities [5], deficiencies in drainage facilities [6], slope defects [7], pre-existing flaws in protective and retaining structures [8], as well as shoulder defects [9]. Failure to promptly identify and rectify these imperfections may engender risks to traffic safety, escalate operational expenses, and directly impact the road's longevity.…”

Advances in Condition Monitoring of Railway Infrastructure

“…As indicated above, the contributions span diverse geographical regions, encompassing specific country cases such as China, Spain, Poland, Ireland, France, Portugal, Netherlands, and Germany. The topics covered include AI (1,3,4,6), track monitoring approaches (1 and 4), wayside wheel defect detection (6), freight wagon digitalization (5), digital twins (7), Structural Health Monitoring (SHM) (9), and tunnels (10). Contributions 4, 6, and 9 entail numerical studies, while contributions 1, 2, 3, 5, 7, and 8 involve experimental field tests.…”