## 3 Results and Discuss
### Snow Cover Distribution Pattern  
This section examines the characteristics of snow distribution on the embankment section with a model height of 10 cm (corresponding to an actual height of 3 m) under nominal wind speeds of 5.5 m/s, 6.5 m/s, 7.5 m/s, and 8.5 m/s, respectively. Additionally, embankments with model heights of 3.3 cm (actual height of 1 m) and 20 cm (actual height of 6 m) were also considered. In the wind tunnel, a 20 mm thick layer of particles was uniformly distributed in the test section to simulate the initial snow cover, and each blowing test lasted for 10 min. Figure 11 shows the comparison of the snow distribution before and after each experiment. Figure 12 depicts the particle distribution along the central axis of the embankment under different wind speeds and embankment heights. To provide a more intuitive representation of the particle accumulation depth distribution, the snow distribution coefficient is defined as follows:  
\[r_{s}=\frac{h_{s}}{h_{c}}, \tag{1}\]  
where, \(h_{s}\) is the snow cover thickness measured after the test and \(h_{c}\) is the snow cover thickness measured before the test. Overall, the snow distribution is consistent across different embankment heights, and exhibits characteristics typical of five areas. Area I, extending from the windward front to the foot of the embankment slope, experiences significant erosion. The distribution coefficient of snow cover in this area is less than 1, indicating that snow particles were removed by the wind. Area II, located on the windward slope, is characterized by snow particle accumulation, which gradually decreases along the wind direction, reaching its  
Figure 11: Comparative photographs. (**a**) Before the experiment; (**b**) After the experiment. Figure 10: Distribution of wind field on the surface of the embankment at different heights. maximum at the foot of the windward slope. Area III, the embankment surface area, undergoes the most severe erosion, with a substantial amount of particles being carried away by the wind, resulting in a snow cover distribution coefficient that is significantly less than 1. Area IV, the leeward slope surface, exhibits substantial particle accumulation, increasing along the wind direction and peaking at the foot of the slope. Area V, extending from the foot of the leeward slope outwards, shows a reappearance of erosion. Comparison with field-measured data reveals a similar \"u\" shaped distribution for the snow distribution coefficient in the wind tunnel tests. At lower wind speeds, particles initially accumulate at the foot of the embankment slope and gradually shift towards the subgrade surface. As the embankment height increases, the accelerated wind field causes particles on the embankment surface to be removed and deposited on the leeward slope. With increasing test wind speed, particle accumulation at the foot of the windward slope increases. However, at excessively high wind speeds, particles are more readily carried away by the wind, leading to increased accumulation at the foot of the leeward slope and reduced accumulation on the embankment surface. This indicates that, under strong wind conditions, particles are more likely to be transported away, hindering accumulation on the embankment surface. The primary differences between the tested conditions are as follows: For a given embankment height, increasing wind speed leads to greater deposition at the front foot of the slope (Area II), increased erosion (and thus less deposition) on the embankment surface (Area III), and higher deposition in Area IV. For a given wind speed, increasing embankment height results in greater deposition in Areas II and IV, but also greater erosion (less deposition) in Area III. This is attributed to the significant influence of embankment height on the wind-snow flow field. As embankment height increases, the wind speed on the embankment surface also increases, facilitating the movement of particles across it and consequently reducing snow particle accumulation.