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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。
The erosion mechanism of overburst collapse of non-viscous dammed dam body considering seepage is studied by the model test of tank. Combined with the experimental data, the relationship between the same stage flow conditions and dam erosion was analyzed. The results show that the process of the dam dams is divided into five stages: the seepage erosion, the formation of the initial collapse point II, the eroded backtrack Ⅲ, the undercutting of the Ⅳ breach (flood peak process) and the Ⅴ roughening and rebalancing. The development of the collapse mainly focuses on the stage Ⅲ-Ⅳ. The process of the collapse of flood peak is related to the length of the crest and the flow of incoming water. The shorter the length of the dam, the larger the flow rate of the dam, the earlier the flood peak is and the smaller the flow rate is. , Breach mouth broadening and undercutting co-exist stage, broadening rate of greater impact on traffic changes. In addition, a preliminary study on the mechanism of spreading and undercutting during the development of the collapse shows that the mechanism of slope sediment start-up can well explain the observed phenomena.