摘要
为揭示不同防沙措施影响下风沙流结构及其携沙粒度变化规律,采用木质和尼龙网2种材料制作方格沙障、单行沙障、双行沙障与挡沙墙4种防沙措施模型,利用风洞实验对防沙措施前后风沙流结构进行测定,并结合Mastersizer3000激光粒度分布仪对沙样进行粒度组成分析。结果表明:(1)不同防沙措施迎风侧风沙流垂直分布与未设置防沙措施时基本相似,输沙量随高度的增加而减小,88%以上的输沙量集中在0~10 cm高度层;而背风侧输沙量随高度表现为先增大后减小的变化规律,且随着沙障规格的减小、高度的增加、行间距的变窄、孔隙度的降低输沙量集中范围逐渐向上偏移,输沙量峰值出现的位置由高度较低的透风型方格沙障(7 cm)上移至高度较高的不透风型挡沙墙(26 cm),且近地表0~10 cm高度层积沙量越少。(2)受不同防沙措施影响,不同高度层沙粒粒度特征差异显著,整体表现出随着高度的增加沙粒的平均粒径逐渐减小的变化规律,细沙和中沙主要分布在近地表5~25 cm层,而近地表0~5 cm层则分布有细沙、中沙和粗沙,峰值出现在0.300 mm附近,平均含量约为12.09%;粒度参数变化受防沙措施规格变化影响较小,更多表现在高度层的差异,不同防沙措施各高度层沙粒分选性较好、极正偏,峰度随防沙措施参数的密集化由宽平向中等、尖窄变化,由方格沙障(0.990)、单行沙障(0.990)、双行沙障(0.996)向挡沙墙(1.086)变化,且上述变化规律随指示风速的增大逐渐增强。
In order to reveal the characteristics of wind-sand flow and sand-carrying grain size,four types of sand control measures were implemented:checkered sand barriers,single-and double-row sand barriers,and retaining walls made of wood and nylon net.Wind tunnel experiments were carried out at Key Laboratory Desert and Desertification,Chinese Academy of Sciences,Lanzhou City,Gansu Province,China to measure the aeolian flow before and after intervention,and the particle size composition of sand samples was analyzed using a Mastersizer3000 laser particle size distributor.The results show that:(1)the vertical distribution of wind-sand flow with the use of various measures was similar to observations made prior to intervention.Sediment transport increased with increases in height,and more than 88%of the sediment transport was concentrated within the 0-10 cm height layer.Also,leeward side with high-sediment discharge performance first increased and then decreased.It also increased with a decrease in the barrier size,height,line spacing of the narrowing,and porosity,and gradually reduced the upward migration of the sediment discharge concentration.Furthermore,the peak value of sediment transport shifted from the relatively low barrier-type drafty squares(7 cm),upward to the relatively high tight sand retaining wall(26 cm).Moreover,the sediment deposition of the 0-10 cm layer near the surface was less.(2)Affected by the various sand prevention measures,significant differences were found in various levels of sand grain size characteristics and the overall average particle size of sand showed decreases with the increase in height,the change rule of fine sand and sand was mainly distributed in the near surface 5-25 cm layer.Meanwhile,the near surface layer 0-5 cm distribution of fine sand,medium sand,and coarse sand,had a peak value of about 0.300 mm,and the average content was about 12.09%.Smaller grain size parameters were affected by the measured specification changes;the kurtosis changes from wide and flat to medium and narrow with the densification of measured parameters;the change from checkered sand barrier(0.990),single-row sand barrier(0.990),double-row sand barrier(0.996)to sand retaining wall(1.086);and the above change law gradually increased with the increase in indicated wind speed.
作者
闫敏
左合君
贾光普
席成
YAN Min;ZUO Hejun;JIA Guangpu;XI Cheng(College of Desert Control Science and Engineering/Inner Mongolia Key Laboratory of Aeolian Physics and Desertification Control Engineering,Inner Mongolia Agricultural University,Hohhot 010011,Inner Mongolia,China)
出处
《干旱区地理》
CSCD
北大核心
2022年第5期1513-1522,共10页
Arid Land Geography
基金
内蒙古自然科学基金项目(2021SHZR0524)资助。
关键词
风速廓线
风沙流
粒度垂直分异
防沙技术措施
wind profile
wind-sand flow
vertical distribution of grain size
sand prevention technology measures