Abstract:

The soil in Wulanbuhe Desert area frozes in winter， and the dry sand on the surface of the flowing sand dunes exposes and is frozen after wind erosion， so the wind and sand movement environment changes. In this paper， the influence of freezing on the wind erosion process is analyzed， and the influence of freezing on the wind erosion process under different moisture conditions is explored. The wind speed gradients of 5， 7， 8.5， 10， 12 m·s^-1 were set up， and 6 gradients of soil moisture content （1%-6%） were set， and non-frozen soil with low moisture content （CK，0.13%） as the control. It is found that a stable frozen layer can be formed within 2 hours on aeolian sand foundation with a water content of ≤2%， while a stable frozen layer can be formed in 5-12 hours on a aeolian sand foundation with a water content of ≥3%.Under the same water content condition， the erosion rate of aeolian sand after freezing increases with the increase of speed， and the wind erosion rate Q and wind speed V conformes to the index Q=ae ^bV . Under the same wind speed， the wind erosion rate of frozen aeolian sand decreases with the increase of soil moisture， and the wind erosion rate and the moisture content w of frozen aeolian sand soil correspond to the exponential function Q=ce ^dw . In general， the wind erosion rate of frozen aeolian sand soil is reduced by more than 40% compared with that of dry sand， and the relationship between wind erosion rate of frozen aeolian sand soil and wind speed and moisture content is consistent with Q=0.367e^{0.849V-0.677w} （R²=0.994）. The wind erosion rate of frozen aeolian sand is reduced by 40%-98% compared with that of CK， and the water content of frozen aeolian sand is more than 3%， which can effectively inhibit wind erosion. Wind speed and moisture content are the main factors affecting the erosion rate of frozen aeolian sand. In the case of future warming and drying， wind erosion in Wulanbuhe Desert may increase.

Key words: wind erosion rate, freeze, soil moisture, wind tunnel test