Compare to common river bed, the erosion and deposition of debris flow gully have a distinctive phenomenon except big changes of scour depth and deposition thickness. Due to its particularity, the process of gully erosion and deposition, variation of gully longitudinal slope is hardly obtained from field survey and observation. The paper analyzed the research of variation of gully erosion and deposition firstly, then prior to probe the changes of gully surface elevation under debris flow erosion, the variation laws of longitudinal slope of gully with debris flow density, initial angle of gull slope and bed materials through flume experiments.

Debris flow sabo dam is one of the most widely used debris flow control engineering. Its stability and safety operation is a key to controlling the effect of hazard prevention and avoiding secondary hazard. Because of the particularity of debris flow, it's very hard to observe the process and morphology directly by field investigation. Although the scouring depth calculation method in hydraulic engineering provide an idea for debris flow sabo dam, but it can't be used directly for the calculation of scouring depth downstream of debris flow sabo dams and foundation designation of the control engineering. This paper analyzed the influence factors of scouring laws downstream of debris flow sabo dams and the research status home and abroad. It suggests studying the scouring process and laws downstream of debris flow sabo dams by theoretical analysis, mechanical analysis and energy method combined with simulation experiments, establishing quantitative relationship between the scouring laws, limited depth, morphology, sediment transportation characteristics and the feature parameters of debris flow.