透过型泥石流拦砂坝工程减灾效果分析

Investigation of effectiveness of open check damsin debris-flow hazards mitigation

为了更好地理解透过型坝的减灾表现,通过对岷江上游、安宁河流域已建的透过型坝开展无人机航测、泥石流取样、室内分析测试等工作,将坝体开口形式分为横向开口、竖向开口、方形开口和混合开口4种类型,研究结果表明:区内透过型坝结构主要以方形开口为主,拦砂坝满库和半库工况占比分别为33.65%和40.38%;回淤纵坡经验值S dep=(0.31~0.83)S init,整体都表现出较好的回淤缓坡效果;在调控方面,透过型坝表现出一定的拦粗排细特征,但由于坝体开口较小,其对粒径的分选效果并不显著;透过型坝减灾中存在坝(群)开口参数设计不合理、坝体结构整体性较差、过流结构的磨蚀破坏、坝下游冲刷侵蚀和基础淘蚀破坏以及库内人工清淤不当等问题。研究成果完善了透过型坝的结构分类,加深了对其功能性的认识和理解,明确了工程实践中的问题与不足,可为工程优化设计提供技术支撑。

With the aim to better understand the performance of open-type check dam against debris flow,a detailed field investigation of open check dams in upper Min River and Anning River was done.In this paper,a classification of open check dams was proposed,including horizontal opening,vertical opening,frame opening and compounded opening.The results indicated that the frame opening was the most open structure of dams.The work situations of full and half reservoir take 36.65%and 40.38%,respectively.And the S dep/S init was ranged from 0.31 to 0.83.The dams performed a regulating function to material size,but the sorting effect was not significant due to the small opening size in practice.Finally,it indicated that the safety of current situation of open check dams dominated by several issues,namely,unreasonable design of opening size,poor structural integrity,abrasion damage of spillway,foundation erosion and improper artificial dredging.The research results can provide a technical support and reference for optimal design of open check dam.