中国水土保持科学2017，Vol.15Issue(6)：19-26,8.DOI:10.16843/j.sswc.2017.06.003
堰塞坝溃口展宽过程实验研究
Experimental study on breach broadening process of landslide dam
摘要
Abstract
[Background] Dynamic process of water and breach determines breach's profile during dam overtopping process.Dynamic processes in different sections along a breach are influenced by different flow regime.At present,research on breach broadening process is mainly focusing on a certain section and assumed this section could represent the broadening process of a dam.Knowledge of breach broadening in every section is short and the whole broadening process of a breach is a scientific question.[Methods] In order to study the whole breach broadening process in different initial conditions (height and slope),six flume experiments were designed to research.The observed data of 45 sections aimed at understanding erosion process in different sections and the influences of these initial conditions.We measured this process by using measure tools in mm accuracy and it was recorded by setting HD camera upon breach initially.Apart from this,the mechanical parameters such as the rate of water content and the density of dam were rigorously controlled for guaranteeing the same mechanical set.[Results] 1) With the development of overflow,this process could be classified into two stages according to breach's profile.The process before the end of retrogressive erosion stage was named as the Aequilate Stage,and the process after retrogressive stage was named as the Bending Stage.In the first stage,the mechanism of water and sediment is simple but in the second stage the mechanism of water and sediment is complicated.2) Broadening process could be divided into two modes,one is Linear Mode and another is Mutation Mode,accounting for 13.3％ and 86.7％ of 45 sections respectively.The Mutation Mode can be further divided into Weak Erosion Process Ⅰ and Strong Erosion Process Ⅱ,in which the process Ⅱ occurs only in the Bending Stage.3) The scour rate in the upstream and downstream is larger than that in the middle.The distribution of scour rate is like "U".In the first process,dam in larger initial slope causes larger scour rate in the same section.With the development of overflow,the complex flow regime has obvious secondary flow characters leading to the scour rate along the breach like "S" during process Ⅱ.For both processes,higher dam height leads to greater erosion rate.[Conclusions] Broadening ratio is different in different section and initial conditions influence the broadening ratio along the breach,which is a complicated process.This study didn't propose formulas to calculate erosion ratio along the breach,because 6 experiments couldn't reflect the physic of broadening process.Apart from this,the new understanding of broadening process of landslide dam is beneficial to the further study of mechanism of this process.关键词
堰塞坝/漫顶溢流/溃口展宽/侵蚀率/溯源侵蚀Key words
landslide dam/overtopping process/breach broadening process/scour rate/retrogressive erosion分类
矿业与冶金引用本文复制引用
刘定竺,崔鹏,蒋德旺..堰塞坝溃口展宽过程实验研究[J].中国水土保持科学,2017,15(6):19-26,8.基金项目
中国科学院重点部署项目“泥石流动力过程及调控模拟”(KZZD-EW-05-01) （KZZD-EW-05-01）
国家自然科学基金国际合作重点项目“气候变化条件下高山区特大泥石流灾害链动力过程与风险分析”(41520104002) （41520104002）
