A Review:Design of debris flow drainage canal

Debris flow is one of the most common geo-hazards in China,which occurred more actively after 5.12 Wenchuan Earthquake.Debris flow drainage canal——a simple and applicable countermeasure acts a significant role in the mitigation and prevention of debris flow.This paper briefly presents the development history of drainage canal,as well as the difference between two common types of drainage canal from such aspects as structural characteristic,drainage principle,advantages or disadvantages and applicable scope,and due to the special characteristic of clearing sands with converging flow,V type drainage canal is more appropriate for the areas where there are more open spaces or the main stream has adequate ability of transport;on the contrary,with the help of submerged sil,l"Dongchuan type"drainage canal can be used in the areas in which there are many infrastructures,like railways,factories,etc. Also,some research achievements on debris flow drainage canal are introduced from the optimization of transverse and vertical section,selection of materials:1)the rational longitudinal slope is 3-10°;2)hydraulic conditions of such types of drainage canal as rectangle/trapezoid,circle,V type are discussed;3)high strength concrete is tried to be used in the construction of drainage canal to enlarge service life;4)a variety of factors in the construction of drainage canal are synthetically considered,such as geological background,hydrologic conditions,ease of construction,etc. In view of deficiency of present researches,it is suggested that more model tests should be conducted in the future to prefect optimization designation of debris flow drainage canal,especially including the study of ecotype drainage canal with indented-sill.