关键词: 复杂山区, 风场特性, 桥隧连接段, 数值模拟, 风攻角

Abstract:

The complex and variable mountainous area causes the wind field to exhibit unsteady and non-stationary characteristics, posing significant challenges to traffic safety at bridge-tunnel connection sections. To study the variation law of the spatial characteristics of the wind field at the bridge-tunnel connection sections in complex mountainous area, this paper takes the mountainous terrain within an 8 km diameter range at the junction of G318 and S217 as the research background. It acquires the digital elevation model (DEM) of the study area’s terrain, and utilizes a reverse fitting method to construct mountain mass models for bridge-tunnel connection sections of five varying lengths. With reference to the standard 16-point wind rose diagram, inflow conditions were configured. The spatial distribution characteristics of wind fields at bridge-tunnel connection sections under various inflow conditions were obtained through numerical simulation. The results show that the error between the numerical simulation results and the on-site measured data is generally within 20%, indicating that the numerical simulation method has high accuracy. Under the condition that the slope of the mountain remains approximately unchanged, affected by the actual complex terrain, cross-bridge wind speeds, vertical wind profiles, and wind attack angles exhibit distinct characteristics at bridge-tunnel connection sections of varying lengths, though they demonstrate similar overall patterns. When the incoming flow is perpendicular to the bridge-tunnel connection section, the wind speed reaches the maximum at the mid-span due to the canyon acceleration effect. This acceleration effect increases as the length of the bridge-tunnel connection section decreases. Under other cases, due to the reduction effect of the high and steep mountains on both sides, the incoming flow decreases and the wind speed is the minimum along the bridge-tunnel connection section. The steep mountainous terrain and river bends significantly influence the vertical cross-bridge wind speed distribution. Within lower-elevation canyons, shorter bridge-tunnel connection sections experience more pronounced effects. Wind attack angles also exhibit substantial terrain-induced variations, predominantly manifesting as negative attack angles overall. The variation laws obtained from the numerical simulation study of the wind field in the bridge-tunnel connection section of complex mountainous areas can provide certain guidance and reference for the study of driving safety at bridge-tunnel connection sections.

Key words: complex mountainous area, wind field characteristic, bridge-tunnel connection section, numerical simulation, wind attack angle