水保所知识产出(1956---)知识库

The detachment rate of partially thawed frozen soil supplies data sets to compute the soil erodibility and critical
shear strength in rill erosion model. This research aims to investigate the effect of slope gradient, flow rate, and
thawed soil depth on detachment rate under partially thawed condition. The detachment rates of partially
thawed soil rill were estimated under three thawed soil depths (1, 2, 5 cm), four slope gradients (5 ◦ , 10 ◦ , 15 ◦ ,
20 ◦ ), and three flow rates (1, 2, 4 L/min). They were then computed with the sediment concentrations measured
along different slope lengths of 0.5, 1, 2, 3, 4, 5, 6, 7, 8 m. Results show that the detachment rates on a partially
thawed soil slope as a function of rill length are piecewise functions, which initially maintain a constant value
before decreasing exponentially with rill length. In the constant detachment rate section, the constant detach-
ment rate increased with thawed soil depth. After the constant detachment rate section, it increased with slope
gradient and flow rate but decreased with the increase in thawed soil depth. The detachment rate decreased fast
with the increase in slope gradient and flow rate. The computed detachment rates fitted by stepwise functions
produced high coefficient of determination, thereby indicating a good correlation of detachment rate with rill
length. The parameters, critical rill length, constant detachment rate, potential detachment capacity, and
reduction coefficient of detachment rate in the piecewise function were regressed with stepwise regression
method. They determined the effects of those four parameters on detachment rate. The influence of flow rate on
critical rill length and thawed soil depth on reduction coefficient of detachment rate was limited. The combined
impacts of slope gradient and flow rate were positively related to those four parameters. This study quantified the
effect of slope, flow rate, and thawed soil depth on detachment rate and help to quantify the soil detachment rate
in cold region.