Abstract:

Compared to traditional Salixpsammophila sand barriers which should be manually inserted one by one， brush shaped S.psammophila sand barriers use mechanical weaving to form bottle brush barriers， which have a shape similar to horse resistance. This kind of barriers are easy to construct and have good stability after setup. Wind tunnel experiments were conducted to study sand fixation function of a brush shaped sand barrier made from S.psammophila branches. The results show that： （1） The wind speed slightly decreases in front of the first row of barrier， and increases significantly at position of the first， the second and the forth row of barrier. After pass through each row barriers， wind speed reduced greatly and formed deceleration zone. （2） The sand surface directly below the barrier often exhibits erosion effect. The erosion phenomenon is the most severe right under the first row barrier， and excavation occurs with time lapse. Between the sand barriers， the sand surface showed a state of accumulation， the first checkerboard accumulated the most severe， followed by a decrease in the degree of accumulation. （3） After setting up the barrier， the structure of the wind-sand flow exhibits a complex exponential decline curve. The sediment collection at wind speeds of 8 m·s^-1， 12 m·s^-1， 16 m·s^-1， and 20 m·s^-1 decreased by 86.8%， 81.6%， 53.4%， and 67.8%， respectively. This indicates that the brush shaped sand barrier has good sand fixation performance. Due to the disturbance of barriers， sand material drifts upwards， resulting in an increase in the amount of sand collected at the sand inlet above a height of 10-14 cm.

Key words: Salix psammophila, brush shaped sand barrier, wind tunnel simulation, sand fixation