堰塞坝溃口展宽过程实验研究

发布时间：2018-06-07 17:05

  本文选题：堰塞坝 + 漫顶溢流　； 参考：《中国水土保持科学》2017年06期

【摘要】：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。
[Abstract]:Because the action of water and sediment is very different and the process of widening is different in different positions, the research on the widening process of the burst is mainly focused on a certain section at present, which can not only not reflect the whole widening process of the burst. It will also affect the accuracy of outburst flow calculation. In order to study the whole widening process of the burst under different dam heights and the ratio of the back slope of the dam, this study designed six groups of flume experiments, and analyzed the observation data of 45 sections. It was found that the expansion of the break showed different forms with the development of overflow. Taking the end of traceability erosion as time node, the period of traceability erosion as near equal width stage, and the bending stage at the end of traceability erosion, the broadening model can be divided into linear model and abrupt mode on the cross section. The mutation model can be further divided into weak erosion process 鈪，

本文编号：1991932