## 4 Validation and Analysis of Results
### Kinetic Analysis of the Source Distribution of Sand-Embedded Particles in Road Embankments  
2.1 Analysis of the Source of Sand-Embedded Particles in Road Embankments with Different Wind Speeds  
As shown in Figure 14, the sand concentration on the embankment varies under different wind conditions. The higher the wind speed, the higher the concentration of sand particles on the embankment surface and at the foot of the leeward slope as the wind speed increases. This illustrates that the higher the wind speed, the more sand particles collide, the more kinetic energy the sand particles gain, the more likely they are to leap over the embankment, and the more severe the sand buildup.  
As shown in Figure 15, the analysis of the sources of sand-buried particles shows that the sources of sand-buried particles are mainly concentrated in the range of 0.004 m-0.0009 m. However, as the moored wind speed increases, the source range remains almost unchanged, but the peak point shifts left and rises. The greater the wind speed, the greater the kinetic energy gained by the sand particles, and the more jumps occur in the sand particles, the shorter the time for the wind-sand flow to reach equilibrium and the peak of the initial distribution of sand-buried particles is shifted to the left. This is the exact reason for the different sand concentrations under different wind speed conditions, as in Figure 14, and verifies the correctness of the particle backtracking algorithm.  
Figure 14: Distribution of sand concentration at different wind speeds.  
Figure 13: Comparison of sand velocity distribution.  
As shown in Figure 16, the windbreak embankment sand concentration distribution. Almost no sand particles were present on the embankment surface for the three wind speed conditions. Sand concentrations on both windward and leeward slopes were reduced to less than 5%. Sand concentrations in front of the windbreak gradually increased with increasing wind speed, while random fluctuations in sand concentrations were observed in the vicinity of the windbreak and behind it. After crossing the leeward slope, the effect of concentration on the variation of wind speed decreases and gradually converges.  
As shown in Figure 17, a comparison of the sand velocity distribution before and after the installation of the windbreak. As shown in Figure 17a, due to the embankment's disturbance of the flow field, the particle velocity at the windward slope of the embankment decreases substantially, preventing the transport of some sand particles. Then, the sand particles move to the leeward slope; due to the turbulence of the airflow field, the sand particles constantly collide and the kinetic energy of the particles increases. It is worth noting that the higher the wind speed, the more pronounced the turbulence of the airflow field and the greater the kinetic energy the sand particles gain. The windbreak-embankment sand velocity distribution is shown in Figure 17b, and the sand velocity around the windbreak and the embankment is significantly reduced. This is due to the obstr  
Figure 16: Distribution of sand concentration in embankment windbreaks.  
Figure 15: Distribution of initial positions of sand-buried particles at different wind speeds.  
wall and barrier; the flow field around the retaining wall and embankment is disturbed to form a wind speed attenuation zone, and then effective sand blocking can be carried out. From the comparative analysis of (a) and (b), it can be seen that after setting up the windbreak, the windbreak interferes with the airflow field, and the flow field around the windbreak is disturbed, which reduces the kinetic energy of the sand particles.