沙尘暴过程中颗粒对化学结皮的冲蚀破坏

Erosion Destruction of Chemical Crust in Dust Storm

针对风沙运动中结皮冲蚀破坏及其寿命问题,通过建立沙粒对结皮的冲蚀模型,采用量纲分析研究风沙运动中单颗沙粒对结皮冲蚀量与沙粒冲击速度、沙粒自旋角速度、沙粒直径、沙粒入射角、结皮硬度等的本构关系,并对结皮冲蚀破坏机理及其寿命预测进行理论研究。数值计算结果表明,沙粒冲击速度、沙粒自旋角速度、沙粒冲击角度、沙粒直径及沙尘暴日数、持续时间都对结皮寿命有明显影响。统计分析各项影响因素的平均值计算表明,在结皮厚度20 mm的情况下,结皮寿命为3～8年,平均寿命5.3年。此研究可以更深刻认识结皮的自然破坏特征,对防沙固沙具有一定的理论意义和实际应用价值。

Crust is a compact soil layer which distributes widely in arid and semi arid region to resist wind ero- sion. In this paper the model of crust destruction in wind erosion is suggested to study the crust destruction mechan- ics, and crust life length is forecasted. Dimensional analysis is applied to establish the constitutive equation of crust wind erosion volume with sand continuous impacting. The numerical calculation results show that crust life length is effected obviously by sand impacting velocity, sand rotational angular velocity, sand impacting angle, sand diameter, dust-storms datasets and its duration. Through statistic analysis and calculation with above influencing factors, the crust life length is 3 - 8 years and 5.3 years average when the crust thickness is 20 ram. This research can make people more deeply understand natural destruction features of crust, which has important theoretical significance and practical application value in sand-protecting and sand-binding.