山区河流浅水条件下漂石对河床响应与泥沙补给影响的试验研究

中文摘要: 受暴雨洪水与滑坡、泥石流灾害的影响，山区河流床沙多为宽级配卵砾石泥沙，甚至出现较多的漂石，从而影响近底水流结构与推移质输移特性。基于野外漂石河流的调查，通过概化试验，探讨了漂石颗粒对河床冲淤的影响；对比分析了不同水沙条件下漂石对推移质输沙率过程的影响；根据床面粗化程度与漂石状态相异的两种类型对比试验，探讨了漂石对不同水沙条件下推移质输沙率的影响程度。初步表明：随着漂石颗粒相对暴露度（D/h，漂石等效粒径与平均水深之比）的减少，漂石对其尾部区域水流的混掺越加突出，从而对河床的冲刷能力变大；根据本试验采用的水沙参数，漂石对推移质输沙率的扩大效应为几倍至十几倍。
Abstract:Rainstorm flood, landslide and debris flow frequently occur in mountainous area, and then lots of coarse particles such as pebble, gravel, boulder with wide size distribution have been entered into open channel. Boulders obviously affect characteristics of flow structure and bedload transport around these boulders. On the basis of the field investigation of boulder riverbed and series of flume experiments with limited water depth, the influence of boulder on the riverbed deformation and bedload transport rate have been analyzed and discussed. The results show that the increase of flow turbulence becomes stronger behind the boulder with the decrease of boulder particle relative exposure degree (D/h, ratio between boulder equivalent diameter and mean water depth), the scour ability has been enlarged, and the more bed material were transported. According to the bed surface coarse degree and boulder dissimilar state, several of experimental cases have been carried out in order to understand the variations of bedload transport rate, changes present that the influence of boulder on bedload transport rate may be several times to ten times with the premise of the flow-sediment conditions in this study.