COLLABORATIVE RESEARCH: Experimental Study of Downstream Fining in Coarse-Grained River Channels

合作研究：粗粒河道下游细化的实验研究

• 批准号: 9205483
• 负责人: John Southard
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9205483&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Experimental; Study; Downstream

This is a renewal of a 2-year project whose overall goal is to study downstream fining by aggradation and selective deposition in gravels. The main results so far have produced downstream fining by a factor of two in a channel 50 m long and 0.3 m wide at the St. Anthony Falls Hydraulic Laboratory (SAFHL), demonstrating unequivocally that selective deposition is an effective fining mechanism and that it can be studied in laboratory experiments. In parallel experiments at Johns Hopkins University (JHU), a novel colored-grain system is providing the fractional-transport data base needed to perdict the fining observed at SAFHL. This phrase now involves a series of runs a SAFHL with a channel width of 2.0 m; this will produce braided topography, enabling invesitgation of the effect of lateral sorting and topography on downstream fining. The present fractional-transport program at JHU, will continue adding components on the effect of sediment feed versus recirculation and the influence of small-scale sedimentary features. Finally, a concurrent set of runs at MIT to examine local lateral sorting in a 1.0 m wide channel as well as the effects of varying deposit geometry and percent extraction is planned. This research seems as the first real connection between engineering hydraulics and fluvial sedimentology and represents fundamental research related to sediment transport mechanics.

这是一个为期两年的项目的更新，其总体目标是研究通过砾石中的沉积和选择性沉积进行下游细化。 迄今为止的主要结果已在圣安东尼瀑布水利实验室 (SAFHL) 的 50 m 长、0.3 m 宽的通道中产生了两倍的下游澄清，明确证明选择性沉积是一种有效的澄清机制，并且它可以在实验室实验中进行研究。 在约翰·霍普金斯大学 (JHU) 的并行实验中，一种新颖的有色颗粒系统提供了预测 SAFHL 观察到的细化所需的分数传输数据库。 该阶段现在涉及一系列 SAFHL 河道，河道宽度为 2.0 m；这将产生辫状地形，从而能够研究横向分选和地形对下游细化的影响。 约翰霍普金斯大学目前的分段运输计划将继续增加沉积物供给与再循环的影响以及小规模沉积特征的影响的成分。 最后，计划在麻省理工学院进行一组并行运行，以检查 1.0 m 宽通道中的局部横向分选以及不同矿床几何形状和提取百分比的影响。 这项研究似乎是工程水力学和河流沉积学之间的第一个真正的联系，代表了与沉积物输送力学相关的基础研究。