Through the simulations of freezing and water scouring test

two water discharges (1

2 L/min)

two soil treatments (unfrozen slope

frozen slope) and four sand coverings (0

1

2

3 cm) were compared to study the effects of the different treatments on runoff and sediment yield on the Loess slope. The results showed that:(1) Under the same flow conditions

the initial runoff time of the sand-covered slope was prolonged

and the extension effect was more obvious as the sand cover thickness increased

however

the initial runoff time was shortened by freeze-thaw action. When the peak value increased

the peak current time of output flow and sediment yield were asynchronous. (2) Under different flow conditions

the total output of different slopes was 1.02~1.28 times of that of the control slopes

then the total outputs of freezing slopes and freezing-covered slopes were significantly different from the control slopes (p <0.05). The total sediment yield of the slope was 1.97~10.94 times of that of the control slope. The total sediment yield of the frozen slope

the control-covered slope and the frozen-covered slope were significantly different from the control slope (p < 0.05). (3) Under the different flow conditions

the trend of runoff intensity of the same treated slope is roughly the same with runoff time. The trend of the runoff intensity of bare slope is steady with the runoff time; however

the runoff intensity's fluctuating degree is larger. Sand cover is the main factor affecting the sediment yield of slope. Under the same flow rate

the runoff intensities of different treatment slopes were roughly divided into two kinds

"rapid rise-relatively stable" and "relatively stable". (4) Under the same flow conditions

the runoff intensity on the bare slope was greatly influenced by the freeze-thaw action. The effects of freeze-thaw and the overburden slope on the sediment yield were large

and the effect of freeze-thaw on sediment yield was greater to bare slope than that to sand-covered slope. The effect of sand cover on the sediment yield was greater than that of the soil under unfrozen soil condition.