| 堰塞坝溃口展宽过程实验研究 | |
| Alternative Title | Experimental study on breach broadening process of landslide dam |
刘定竺1,2 ; 崔鹏1; 蒋德旺1,2
| |
| Corresponding Author | 崔鹏 |
| 2017 | |
| Source Publication | 中国水土保持科学
 |
| ISSN | 2096-2673 |
| Volume | 15Issue:6Pages:19-26 |
| Subtype | Article |
| Contribution Rank | 1 |
| Abstract | 由于溃口各处水沙作用差异较大,不同位置的展宽过程不同,目前对溃口展宽过程的研究多着眼于某一断面,不但不能反映溃口整体的展宽过程,还会影响溃决流量计算的精度。为研究不同坝高、坝后坡比条件下溃口整体展宽过程,本研究设计了6组水槽实验,分析了45个断面的观测数据,发现: 1)溃口展宽随溢流的发展表现出不同的形式,以溯源侵蚀的结束为时间节点,溯源侵蚀期间为近等宽阶段,溯源侵蚀结束后为弯曲阶段。2)在断面上,展宽模式可分为线性模式和突变模式,分别占45个断面的13.3%与86.7%;突变模式进一步可分为弱侵蚀过程Ⅰ和强侵蚀过程Ⅱ,其中强侵蚀过程只发生在弯曲阶段。3)突变模式下,过程Ⅰ侵蚀率沿程呈首尾大-中部小的U型分布,溃口首部和溃口尾部侵蚀率较大,中间近等宽段侵蚀率有所减小,坝后坡比越大,该过程中溃口相同位置处的侵蚀率越大;随着溢流的发展,水流结构复杂,具有明显的二次流特征,导致过程Ⅱ的侵蚀率沿程分布呈S型;对2个过程而言,坝高越高,相同位置处的侵蚀率越大。上述对于堰塞坝溢流展宽过程的新认识,有益于今后深入定量研究溃口展宽过程和力学机理。 |
| Other Abstract | [Background]Dynamic process of water and breach determines breachs 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 breachs 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 ProcessⅠand Strong Erosion Process Ⅱ,in which the processⅡ 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 likeU. 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 likeSduring 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 didnt propose formulas to calculate erosion ratio along the breach,because 6 experiments couldnt 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. |
| Keyword | 堰塞坝 漫顶溢流 溃口展宽 侵蚀率 溯源侵蚀 |
| DOI | 10.16843/j.sswc.2017.06.003 |
| Indexed By | CSCD |
| Language | 中文 |
| CSCD ID | CSCD:6150720 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.imde.ac.cn/handle/131551/23050 |
| Collection | 山地灾害与地表过程重点实验室 中国科学院水利部成都山地灾害与环境研究所 |
| Affiliation | 1.中国科学院山地灾害与地表过程重点实验室/成都山地灾害与环境研究所; 2.中国科学院大学 |
| First Author Affilication | 中国科学院水利部成都山地灾害与环境研究所 |
| Recommended Citation GB/T 7714 | 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. |
| APA | 刘定竺,崔鹏,&蒋德旺.(2017).堰塞坝溃口展宽过程实验研究.中国水土保持科学,15(6),19-26. |
| MLA | 刘定竺,et al."堰塞坝溃口展宽过程实验研究".中国水土保持科学 15.6(2017):19-26. |
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