## 1 Introduction  
Global deserts and desertification lands cover more than 7 \(\times\) 10\({}^{6}\) km\({}^{2}\) areas of the Earth. Since the 1990s, the desertification area has expanded at the rate of 2460 km\({}^{2}\) per year, causing a significant impact on human production and living activities and a global economic loss of more than USD 42.3 billion each year [1]. The main hazards of wind-sand flow on desert roads include sand burial and wind erosion [2]. Sand burial refers to the movement of wind and sand to the vicinity of the roadbed; the roadbed structure im-pedes the movement of wind and sand to the downwind side so that the wind and sand flow from an unsaturated state to a saturated state. This results in the accumulation of sand particles at different positions on the roadbed [3]. Many researchers have analyzed the flow field characteristics of windbreaks and the structural characteristics of wind and sand flow through on-site observation, wind tunnel experiments, and numerical simulation to obtain optimal windbreak setting parameters. [PERSON] [4] et al. investigated how windbreaks change the trajectory of wind-sand flow and found that the flow field of wind-sand flow over windbreaks varies with different heights of windbreaks, and the accumulation of sand behind the walls is also different. [PERSON] [5] et al. combined wind tunnel experiments and particle image velocimetry to analyze the characteristics of the flow field in the vertical profile of a windbreak on a bridge by investigating the effect of the parameters of the windbreak on the reduction in the wind speed, such as the wind speed, the height of the enclosure, the installation spacing and the number of layers. [PERSON] [6] et al. determined that upright windbreaks provide good shielding by analyzing 3D flow lines and the surface pressure of trains. [PERSON] et al. [7] proved that the geometry of the wind barrier significantly affects the train's aerodynamic force. [PERSON] [8] et al. used wind tunnel tests to explore the critical length of wind barriers of different thicknesses and analyzed the effects of using wind barriers of various thicknesses on the aerodynamic characteristics of trains in wind tunnel tests. According to the existing research, in exploring the process of wind-sand erosion, the existing methods are mainly used to numerically simulate the wind-sand flow by wind tunnel experimental test or Euler-Lagrange method, which analyses the parameters such as the shape, height, width, and porosity of the windbreak primarily. However, all of the above techniques need to divide the grid for analysis, and the small-scale wind-sand flow model is more sensitive to grid distortion. The grid division method seriously restricts the precision and accuracy of the wind-sand flow analysis. Therefore, this paper introduces the Smooth Particle Hydrodynamics (SPH) method to simulate the wind-sand flow numerically. Smooth Particle Hydrodynamics (SPH) is a meshless Lagrangian particle method. In the SPH method, an object is described by a series of particles. These particles carry physical information, such as density and velocity [9; 10]. The technique eliminates the sensitivity of small-scale models to large deformations or distortions of the mesh and allows the tracing of particle trajectories [11; 12]. At the same time, this paper proposes a new optimization method for sand prevention based on the trajectory of particles, i.e., to explore the source of sand particles through the analysis of the concentration, velocity, and particle size distribution of sand particles to optimize the location of windbreaks and to effectively implement sand prevention measures. In this paper, a particle backtracking algorithm based on the SPH method is written in C. This algorithm can realize the capture and analysis of particles' source, concentration, velocity, and particle size distribution and carry out sand blocking and sand treatment by investigating the movement mechanism of sand particles.