Effects of thawed depth on the sediment transport capacity by melt water on partially thawed black soil slope

This study proposed an apparatus for measuring the sediment transport capacity, which is an important parameter for rill erosion prediction and modeling. Laboratory experiments were conducted to measure the sediment transport capacity of partially thawed black soil slope under different hydraulic conditions and thawed depths (five slope gradients of 5 degrees, 10 degrees, 15 degrees, 20 degrees, and 25 degrees; three flow discharges of 1, 2, and 4 dm(3) min(-1); and four thawed depths of 1, 2, 5, and 10 cm). The effect of thawed depth on sediment transport capacity was quantified with experimental data under different slope gradients and flow discharges. A quadratic model was used to relate sediment transport capacity to thawed depth, slope gradient, and flow discharge, and its key factors that influenced sediment transport capacity were determined by using stepwise regression. Results showed that sediment transport capacity decreased with the increase of thawed depth from 1 to 5 cm, but it tended to be steady when the thawed depth was greater than 5 cm. Model-fitting results showed that sediment transport capacity was positively correlated with slope gradient and flow discharge but negatively correlated with thawed depth. The proposed method and experimental device solved the difficulties of insufficient sediment supply on the measurement of sediment transport capability, and it can be used to measure the sediment transport capacity of concentrated water flow under different conditions of slope gradient, thawed depth, and flow discharge. The method is helpful to the research of erosion process of partially thawed soil under concentrated water.