The series of model experiments were conducted by changing rain intensity and rainfall duration, and the relationship between the high intensity sediment transport in the gully due to rainstorm and the accumulation body in the confluence was studied experimentally in laboratory.The results showed that the evolution of the accumulation body synchronized with the location of main-stream in the gully.There was a positive correlation between the times of the main-stream changing and the rain discharge.In contrary,there was a negative correlation between the times of the main-stream changing and the rain intensity.The length and thickness of accumulation body increased with the increase of rain discharge.The gradient of vertical sections was significantly affected by flow structure nearby accumulation bodies.In general,the gradient of section was lowest in all of vertical sections.Meanwhile,either section was largest. In addition,because of the evolution of accumulation body,the section was a multiple accumulation structure. Finally,the longitudinal profile of accumulation body was wedge,and the shape of transverse profile was multi-peak.
