季节性冻融区解冻期土壤分离能力影响因素研究

Study on factors affecting soil detachment capacity of thawing period in the region of seasonal freeze-thaw

季节性冻融区解冻期土壤分离是水力与冻融复合的侵蚀过程,为侵蚀产沙提供了物质储备,是初春河道泥沙的主要来源。以黄河中上游内蒙古段十大孔兑地区砂壤土为研究对象,采用田口方法,对比分析冻融循环次数、土壤初始含水率、坡度和流量对土壤分离能力的影响。研究结果表明：冻融条件下,土壤分离能力与坡度、流量、冻融循环次数和土壤初始含水率均呈正相关关系。当坡度大于10°时,土壤分离能力的增加幅度降低;在本试验条件下,当各因素水平最大时,土壤分离能力达到最大值;各因素对土壤分离能力大小贡献率分别为坡度（76.02%）〉流量（13.39%）〉土壤初始含水率（6.92%）〉冻融循环次数（3.67%）。在降水量有限的解冻期,坡度是影响土壤分离能力的最主要因素;田口方法对土壤分离能力预测相对误差小于20%,预测效果较好。

The effect of hydrodynamic factors and freeze-thaw factors on soil detachment capacity, and the processes of freeze-thaw and soil detachment are studied by using the least time and material resources com- bined with the method of Taguchi test simulation. Results of freeze-thaw and flume scour tests showed that soil detachment capacity increased with the increase of slope, flow rate, freeze-thaw cycles and initial soil water content, under the condition of freezing and thawing. Increasing range of soil detachment capacity decreased when the slope is greater than 10 degrees. Under the experimental conditions, the soil detachment capacity reached the maximum value when the level of the factors was the maximum. The contribution rate of various factors to soil detachment capacity were slope （76.02%） 〉 flow discharge （13.39%） 〉 soil moisture （6.92%） 〉 freeze-thaw cycles （3.67%）. The relative error of the prediction of soil detachment capacity by Taguchi method is less than 20%.