Energy dissipation, scour prevention and reinforcement combined structure for lower stair of debris flow blocking dam

The utility model discloses a lower step energy dissipation, scour prevention and reinforcement combined structure for a debris flow blocking dam, belongs to the technical field of debris flow prevention and control engineering, and aims to solve the technical problems that in the prior art, a loose accumulation layer below a main dam is deep and thick, a local channel longitudinal slope is large, an energy dissipation and scour prevention structure below a single dam is prone to being eroded and damaged, and a channel is violently undercut and eroded. The main dam foundation is damaged and unstable, the blocking function is lost, and even the damage effect of debris flow is aggravated due to dam break. According to the technical scheme, the stepped rib sill structure comprises a main dam and a pile foundation, a plurality of stepped rib sills which are not located on the same horizontal plane are arranged between the main dam and the pile foundation, and flow guide side walls are further arranged on the side