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工程科学与技术:2016,48(4):38-44
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堰塞坝溃口下切过程实验研究
(中科院山地所)
Experiments investigation on longitudinal breachingof natural dam
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投稿时间:2015-12-14    修订日期:2016-03-21
中文摘要: 针对堰塞坝溃口下切过程和不同因素对过程影响的问题,开展了室内水槽实验。结果表明:溃口下切过程分3个阶段,Ⅰ为溃口缓慢发展阶段:为水流缓慢溢出溃口阶段,侵蚀速率较小,泥沙输移主要以悬移质运动为主,溃口下切缓慢;Ⅱ为溃口迅速发展阶段:表现为溯源侵蚀强烈,溃口底部变化迅速,推移质运动占主导地位;Ⅲ为稳定河床形成阶段:水流速度和流深减小,水流携沙力减弱,河床形成粗化层,最终达到新的水沙平衡。溃口流量与侵蚀的关系表现为:来水流量的加大增加了相应时刻的溃决流量,增大了侵蚀率,缩短了溃决时间,溃口底部趋于平滑。来水流量的加大提高侵蚀率曲线斜率,使侵蚀率曲线向瘦高型发展。随背水坡坡度的增加,溃决流量增大,侵蚀率增加,坝体残留高度降低。另外,因背水坡坡度增加导致坡面土颗粒稳定性的降低可采用水槽坡度与背水坡坡度之和的正切值的三次方这一因子反应。最后指出,考虑堰塞坝材料性质差异性的溃决过程是下一步研究的重点。
Abstract:in order to obtain the progress of longitudinal erosion and effects of different factors, we conducted 6 flume tests. The results indicate that: the longitudinal erosion process includes 3 stages. At stageⅠ,the outflow is slow, and the suspended load wastransported to downstream mainly during the process.At stageⅡ, the depth of the breach changed rapidly.The bed load wastransported fiercely due to backward erosion. Atstage Ⅲ, the velocity and rateof outflow decreased, armor layer was formed which protected the sediment under the armor layer from eroding. At last, dynamic equilibrium was achievedbetween the water phase and sediment phase. With inflow rate increasing, the breach time decreases and outflow discharge increases, this leads to greaterstream power and highererosion rate. And the bottom of the breach become smoothly due to large inflow rate. The slope of the erosive characteristics curve becomes larger with the outflow discharge increasing. The shape of erosive curve changes from multi-peak curve to mono-peak curve with downstream slope increasing. The steepslope of downstream also increases the outflow discharge and erosion rate, and decreases the residual height of the dam. The factor J3 which is equal tothe third power of tangent values of the bed slope and downstream slope’s summation, can reflect the stability of soil particles in differentdownstream slopes. The shortcoming of current study is that the effects of material diversity on the dam breaching process was not considered and shall be investigated in the future work.
文章编号:201501345     中图分类号:    文献标志码:
基金项目:中国科学院重点部署项目“典型地质灾害预测预报与防控方法”(KZZD-EW-05-01),国家自然科学基金重大项目子专题“水体多相态转换过程对水资源与水灾害的影响”(41190084),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)。
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jiangxiangang  jxgjim@163.com 
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引用文本:
蒋先刚.堰塞坝溃口下切过程实验研究[J].工程科学与技术,2016,48(4):38-44.
jiangxiangang.Experiments investigation on longitudinal breachingof natural dam[J].Advanced Engineering Sciences,2016,48(4):38-44.