عنوان مقاله [English]
Gully erosion causes a drop in channel bed, widening channel and transport large amount of sediment to downstream. Understanding the effects of various factors such as soil consolidation and the placement of the sandy layer on sediment transport rate are the goals of this research. Therefore, five samples of cohesive soils with various percent of clay and silt with short- and long-term consolidation were tested under natural conditions. Moreover, in one test a sandy layer was laid on the gully bed to study the effects of this layer. Results indicated gully migration to upstream occurred at angles closer to 90 degrees when the percent of clay was raised. The same reduction in clay amount in long- and short-term consolidation caused the total gully migration and amounts of sediment to increase 2.5 times in long-term compared to short-term consolidation. The effect of clay reduction was more pronounced in the sample with long-term consolidation.