Will Wind–Sand Activity Bury the Opencut Tunnel along the Linhe–Ceke Railway, China?

Abstract

The opencut tunnel is a kind of linear arch construction and a new linear sand-prevention structure. In order to clarify the wind-proof mechanism of the opencut tunnel, this paper seeks to answer the question of whether the opencut tunnel of the Lin–Ce railway will be buried. In this paper, a wind tunnel experiment combined with field investigation and testing is used to systematically study the mechanism of wind and sand resistance in an opencut tunnel, and it is verified whether the sand burial of the opencut tunnel is possible. The results show that the airflow greater than 0.7 times of the height is in a state of acceleration and uplift, and no sand-filling phenomenon occurs at the ventilation vent at the top of the opencut tunnel. More than 85% of the sediment transport on the windward side was within the height of 0–10 cm, and 80% on the leeward side was concentrated in the height of 30–70 cm; the greater the angle between the opencut tunnel and the wind direction, the higher the potential of wind and sand resistance. In the past 20 years, no mass accumulation of shifting sand occurred along the opencut tunnel. Furthermore, the shifting sand could not bury the opencut tunnel in the small-scale time range. Wind-field characteristics determine angle between the opencut tunnel and wind direction as 75°−90°, setting the optimal scope of protection. However, different angles can effectively prevent and control sand flow hazards in railways, ensuring smooth railway operation.