Evaluation of sand-fixation effect of different configuration measures of protection system in Wuhai-Maqen Highway in Tengger Desert
Since the Tengger Desert section of Wuhai-Maqen Expressway(G1816)was built,the wind-sand protection system has effectively ensured the safe operation.However,the sand damage in some sections is seri-ous,and sand occasionally covered the road during windy season.Therefore,it has great significance to quantita-tively evaluate the effect of protection system on windstorm and sand fixation.In this paper,the wind-sand activi-ty of two typical sections is observed based on UAV topographic survey and wind condition analysis.The results show that area of wind erosion and sand accumulation in Section K357 protection system of single straw checker-board barriers is large,while the area in section K358 of more measures to windbreak and sand fixation is small-er.The average wind speed and frequency of sand driving wind in straw checkerboard in section K357 are signifi-cantly lower than that of the moving dune area in the upwind direction.While the sediment transport potential in section K357 is lower 36.4％than in moving dune area and the resultant sediment transport potential is lower by 20.7％.In addition,three transverse dunes ranging from 40.2-46.3 m have been formed in the gravel covered ar-ea next to roadbed in section K357.During the observation period,the height of dunes increased by 0.12-0.23 m,and the highest ridge line of the dunes moved by 2.13-2.48 m along the northwest to southeast direc-tion,respectively.The direction of dune movement are consistent with the direction of resultant sediment trans-port potential.However,due to photovoltaic power plant construction in the upwind in section K358,the wind speed in the mobile dune area decreases significantly,and the frequency of sand driving wind at mobile dune is only 5.73％,when the flow field in straw checkerboard barriers area recovers,the frequency of sand driving wind increases to 21.78％.The result showed that establishment of photovoltaic power plant has a positive impact on the highway protection system and highway safety operation.In a word,the wind and sand activities are seri-ous in Wuhai-Maqen Highway in Tengger Desert.Secondary sand damage brings a threat to highway safety oper-ation.It is urgent to further improve the protection system in typical sand-damaged road sections.
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