Abstract: In order to understand the snowdrift characteristics on the subgrade of expressway interchange sections and provide a theoretical basis for future snow fence setting, wind information and snow distribution characteristics of Xialaoba interchange subgrade, which is a section of newly built Jingxin expressway (G7) from Barkol to Mori, were analyzed using wind field monitoring, on-site snow investigation and numerical simulation methods. The wind field monitoring system showed that the wind direction of Xiahaoba interchange area was unstable and the dominant wind direction in this area was northwest wind. Numerical simulation results showed that the height and distance difference between the adjacent two ramps of the subgrade in the interchange section affected the wind speed and snow distribution on downwind subgrade. Under two conditions of 10 m distance and 2 m height difference or 50 m distance and 7 m height difference between adjacent two ramps, the wind velocity of downwind subgrade has decreased about 35% and 53% respectively, while the snow on subgrade increased 14.0% and 18.5%. Accumulated snow survey showed that the snow cover law on the ramp was consistent with the numerical simulation results. Snow prevention facilities should be reasonably arranged outside the interchange according to the snow on the downwind ramp.

Key words: expressway, interchange subgrade, snowdrift, wind speed and direction, snow distribution