Effects of different types of guardrails on sand transportation of desert highway pavement

Guardrail, an important highway traffic safety facility, is mainly used to prevent vehicles from accidentally driving off the road and to ensure driving safety. Desert highway guardrails hinder the movement of wind-blown sand, resulting in the decline of sand transportation by the pavement and the deposition of sand gains on the pavement, and endangering traffic safety. To reveal the influence of guardrails on sand transportation of desert highway pavement, we tested the flow field and sand transport volume distribution around the concrete, W-beam, and cable guardrails under different wind velocities through wind tunnel simulation. Wind velocity attenuation coefficients, sand transportation quantity, and sand transportation efficiency are used to measure sand transportation of highway pavement. The results show that the sand transportation of highway pavement was closely related to the zoning characteristics of flow field and variation of wind velocity around the guardrails. The flow field of the concrete guardrail was divided into deceleration, acceleration, and vortex zones. The interaction between the W-beam guardrail and wind-blown sand was similar to that of lower wind deflector. Behind and under the plates, there were the vortex zone and acceleration zone, respectively. The acceleration zone was conducive to transporting sand on the pavement. The cable guardrail only caused wind velocity variability within the height range of guardrail, and there was no sand deposition on the highway pavement. When the cable, W-beam, and concrete guardrails were used, the total transportation quantities on the highway pavement were 423.53, 415.74, and 136.53 g/min, respectively, and sand transportation efficiencies were 99.31%, 91.25%, and 12.84%, respectively. From the perspective of effective sand transportation on the pavement, the cable guardrail should be preferred as a desert highway guardrail, followed by the W-beam guardrail, and the concrete guardrail is unsuitable. The study results provide theoretical basis for the optimal design of desert highway guardrails and the prevention of wind-blown sand disasters on the highway pavement.