关键词: 沙粒胶结体, 野外验证, 风蚀量, 抗风蚀效率, 固沙效益

Abstract: Taking the sand cemented bodies (SCB) in the hinterland of Taklimakan Desert, Xinjiang, China, as the research object, the amounts of wind erosion, accumulation and anti-erosion efficiency on the surface of sand beds with different SCB coverage were calculated after the field experiment, and the relation between coverage and wind erosion or antierosion efficiency was analyzed. The results of the field experiment and wind tunnel simulation were compared and analyzed at the same time. The results showed that the amount of erosion was decreased with the increasing degree of SCB coverage and was increased with the increasing deflation time. When the coverage was 0%-10%, the surface of sand beds were wind eroded with different deflation time. The sand blown by the wind accumulated on the sand surface when the coverage is greater than 30%, and the accumulation was increased with the increase of coverage and deflation time. The efficiency of antiwind erosion of SCB was increased linearly with the increase of the coverage. The critical coverage is about 30% for the sand surface erosion which means the best effect of antiwind erosion of the sand bed is achieved. The field experimental results were consistent with the windtunnel simulation that the SCB can improve the ability of antiwind erosion of sand beds, and SCB can also capture sand from winddrift sand to generate aeolian accumulation at a given coverage. The wind erosion rate was increased with the increasing wind speed. The bigger the wind speed was, the bigger the critical coverage when erosion was transformed to accumulation will be. However, there were some differences between the field experiment and wind tunnel simulation. Under the conditions of field experiment, the critical coverage was greater than that in the wind tunnel simulation, and for the erosion rate it was the opposite. This was caused by the different wind conditions, wind speeds and particle sizes of the SCBs as revealed by the comparison between the field experiment and the wind tunnel simulation. It was concretely represented in three aspects: Firstly, the wind speed and direction were kept stable in the wind tunnel simulation, while the wind was changeable and complex in the field; secondly, the wind speed in the wind tunnel simulation was higher than the wind velocity threshold for sand emission in the field; and thirdly in the wind tunnel simulation, the same coverage experimental sample was used to place the SCBs of the same particle size range, while the SCB of different particle sizes were collected and placed in the field experiment to reflect its true distribution in nature. In conclusion, the SCB developed in the hinterland of Taklimakan Desert has a good inhibition of wind erosion and can be used as a new measure for quicksand fixation in the desert.

Key words: sand cemented bodies, field verification, wind erosion amount, anti-erosion efficiency, sand-fixing benefits