韭园沟流域典型淤地坝淤粗排细作用研究

对韭园沟流域8座典型淤地坝坝内淤积物进行野外挖探坑观测取样,将坝内淤积物和马兰黄土颗粒级配进行对比,初步分析淤地坝的淤粗排细作用机理。在空间分布上,垂直分布,淤地坝坝内淤积物具有一定的沉积层理,即粉土层与黏土层相间分布;水平分布,同一沟道上游淤地坝较下游淤地坝淤积物粒径粗,单坝远坝处较近坝处淤积物粒径粗。工程结构上,有放水建筑物的淤地坝,控制面积决定了其淤粗排细效果;控制面积相近的淤地坝,有无放水建筑物决定了其淤粗排细效果;水毁坝也具有一定淤粗排细作用。

Functions of Depositing Coarse Sediment and Releasing Fine Sediment of Typical Warping Dams in Jiuyuangou Watershed

The paper initially analyzes the mechanism of depositing coarse sediment and releasing the fine of warping dams through field observation and sampling sediment from eight typical warping dams in Jiuyuangou Watershed,conducting contrastive analysis on grain composition of depositing matter and the Malan loess.On spatial distribution,depositing matter within warping dams has certain depositional bedding in vertical distribution,i.e.alternating distribution of silt and clay.In horizontal distribution,the particle size of depositing matter in the upper stream of warping dam is coarser than that of the closer for one gully,and the particle size of depositing matter in where far from the typical dam is coarser than that of the closer for single dam.On engineering structure,for a warping dam with outlet structure,the controlled area decides the effect of depositing coarse sediment and releasing the fine;for a warping dam with similar controlled area,with or without outlet structure decides the effect of depositing coarse sediment and releasing the fine and;the damaged warping dam also has certain function of depositing coarse sediment and releasing the fine.