水利学报
水利學報
수리학보
2012年
z2期
60-67
,共8页
堰塞坝%溃决机理%非黏性沙%溃口展宽下切%渗流
堰塞壩%潰決機理%非黏性沙%潰口展寬下切%滲流
언새패%궤결궤리%비점성사%궤구전관하절%삼류
natural barrier dam%breach mechanism%non-cohesive sand%expansion and incision of the breach%seepage
通过水槽模型试验研究了考虑渗流情况下非黏性堰塞坝体的漫顶溃决侵蚀机理.结合试验数据,分析了溃坝过程的同阶段水流条件及坝体侵蚀的相互关系.结果表明:堰塞坝溃决过程分为:Ⅰ渗流侵蚀、Ⅱ初始溃决点形成、Ⅲ溯源蚀退、Ⅳ溃口展宽下切(洪峰过程)以及Ⅴ粗化再平衡5个阶段,溃决发展主要集中于阶段Ⅲ—Ⅳ;溃决洪峰过程与坝顶长度和入库流量相关,坝体长度越短,入库流量越大,洪峰越早越“尖瘦”;溃决流量变化与溃口展宽、下切速率相关,溃口展宽与下切同时存在阶段,展宽速率对流量变化的影响更大.另外,对溃决发展过程中展宽和下切的机理的初步探讨表明,斜坡泥沙起动这一机理能够很好地解释观察到的试验现象.
通過水槽模型試驗研究瞭攷慮滲流情況下非黏性堰塞壩體的漫頂潰決侵蝕機理.結閤試驗數據,分析瞭潰壩過程的同階段水流條件及壩體侵蝕的相互關繫.結果錶明:堰塞壩潰決過程分為:Ⅰ滲流侵蝕、Ⅱ初始潰決點形成、Ⅲ溯源蝕退、Ⅳ潰口展寬下切(洪峰過程)以及Ⅴ粗化再平衡5箇階段,潰決髮展主要集中于階段Ⅲ—Ⅳ;潰決洪峰過程與壩頂長度和入庫流量相關,壩體長度越短,入庫流量越大,洪峰越早越“尖瘦”;潰決流量變化與潰口展寬、下切速率相關,潰口展寬與下切同時存在階段,展寬速率對流量變化的影響更大.另外,對潰決髮展過程中展寬和下切的機理的初步探討錶明,斜坡泥沙起動這一機理能夠很好地解釋觀察到的試驗現象.
통과수조모형시험연구료고필삼류정황하비점성언새패체적만정궤결침식궤리.결합시험수거,분석료궤패과정적동계단수류조건급패체침식적상호관계.결과표명:언새패궤결과정분위:Ⅰ삼류침식、Ⅱ초시궤결점형성、Ⅲ소원식퇴、Ⅳ궤구전관하절(홍봉과정)이급Ⅴ조화재평형5개계단,궤결발전주요집중우계단Ⅲ—Ⅳ;궤결홍봉과정여패정장도화입고류량상관,패체장도월단,입고류량월대,홍봉월조월“첨수”;궤결류량변화여궤구전관、하절속솔상관,궤구전관여하절동시존재계단,전관속솔대류량변화적영향경대.령외,대궤결발전과정중전관화하절적궤리적초보탐토표명,사파니사기동저일궤리능구흔호지해석관찰도적시험현상.
Experiments were conducted in the present study to investigate the physics of dam breach pro?cess in natural dams. Upon the observation, the particulars of the breach growth were examined, and the whole breach process could be distinguished into five stages,e.g.,Stage Ⅰ seepage erosion;Stage Ⅱ for?mation of the initial breach;Stage Ⅲ headward erosion;Stage Ⅳ expansion and incision of the breach;and Stage Ⅴ re-equilibration of the river channel through the breach. Based on the experimental data, flood hydrographs coupled with movable boundary development was also discussed. The result shows that the sediment incipient on steep slopes might be an essential mechanism to explain violent expansion and in?cision of the breach during dam breach.
