Wind tunnel simulation of complex deformation law on retaining wall under aeolian sand environment

  Objective  Wind and sand protection is one of the key engineering issues in the construction and maintenance of human infrastructure in arid environment. This paper aims to find out the complex law of wind and sand migration, and to select the appropriate setting parameters of special wind and sand protection system.

  Method  Wind tunnel simulation was used to study the variation of wind velocity field, sand flow structure and sand interception ratio/permeability under different wind direction angles.

  Result  (1) The height of 4 times barrier on the windward side model was always the inflection point of the sharp change of the airflow, and did not change with the indicated wind speed. When the indicated wind speed was less than 10 m/s, the leeward area of weak wind or calm wind area increased with the indicated wind speed, and the opposite law was presented when the indicated wind speed was greater than 12 m/s. Under the action of the same indication wind speed, the effective protection range increased gradually with the increase of wind direction angle. (2) The windward sediment mainly concentrated at 0−10 cm near the surface, accounting for 85.31% of the total sediment transport. The leeward sediment transport under different wind direction angle measures mainly concentrated in the range of 20−30 cm height, accounting for 71.25%, 88.75%, 85.25% and 86.00% of the total sediment transport, respectively. (3) Sand interception in leeward layer at 0−10 cm height increased with the increase of indicated wind speed, and reached the maximum at the included angle of 75°, averaging 95.64%. The sand transport in the 10−30 cm height layer had an increasing trend with the increase of indicated wind speed, and the maximum was 81.09% on average when the included angle was 45°.

  Conclusion  The variation of indicated wind speed has no significant influence on the variation law of the airflow velocity field of retaining wall, but has a greater influence on the leeward side of the weak wind area or the range of the calm wind area, and the effective protection range is the best at 75°. The sand transport on the windward side gradually decreases with the increase of height, while that on the leeward side climb up and then decline with the increase of height. The wind angle should be set at about 75° as a measure to prevent wind and sand.