关键词: 防沙工程, 三维气流场, 阻风效率, 湿度, 粒径, 植物, 临哈铁路

Abstract:

In view of the present situation of sand damage along the Linhe-Hami Railway， three dimensional flow field observation sections were set up in sand control areas along the Linhe-Hami Railway K420 and the Tianehu-Ceke Railway K25. The horizontal and vertical wind speed of mobile point and fixed point were synchronously observed using the three dimensional ultrasonic wind speed sensor， the wind drag efficiency， sand layer humidity， grain size， vegetation characteristic of engineering area were preliminarily analyzed. The results show that the average horizontal wind speed drag efficiency of the sand barrier and the grid is 0.79 and 0.90 at the height of 1 m. The average horizontal wind drag efficiency of the large grid （2 m wide， 50 cm high） at the height of 1m is 0.67， which is better than the 0.75 of the small grid （1 m wide， 20 cm high）. We suggest that the distance between sand barriers should be reduced from the current 35 m to 20 m， so that each sand barrier is in the wind shadow area of the front sand barrier， and more sand is fixed between the sand barriers. The volume humidity of the sand layer in the grid is obviously higher than that of the sand-barrier aeolian sand belt， which usually reaches its maximum at a depth of 20 cm and the deep humidity is more than 4%. The analysis of average particle size of surface sand shows that the sand fixing grid （0.259 mm） >the top of barrier sand belt （0.219 mm） > track （0.146 mm）. The total number of plant species in each sand-control engineering area is 17， among which Haloxylon ammodendron， Caragana korshinskii， Nitraria tangutorum and Artemisia sphaerocephala are the main dominant species.

Key words: sand control engineering, three-dimensional flow field, wind drag efficiency, humidity, grain size, vegetation, Linhe-Hami Railway