Abrasion by Bedload and Suspended Load: Experimental Study

床载和悬载引起的磨损：实验研究

• 批准号: 0943407
• 负责人: Kelin Whipple
• 金额: $ 12.87万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0943407&HistoricalAwards=false
• 关键词: Abrasion; Bedload; Suspended; Load; Experimental

Abstract: ASU Flume Study ?Abrasion by Bedload and Suspended Load: Experimental Study?River incision into rock plays an important role in diverse problems ranging from practical to academic. From dam spillway design, to river management planning including maintenance of suitable aquatic habitats in mountain rivers and river restoration efforts, to the long-term controls on the slope, width, and roughness of mountain rivers, a quantitative understanding of the mechanics of river incision into rock is essential and of broad interest. There has been substantial progress in the past decade on understanding the interactions among climate, topography, erosion, and tectonics; recognition of the central role of river incision into rock has been a key insight. Exploration of the role played by bedrock channels, however, has been accomplished primarily with simplified stream power models (generic rule sets for river incision that lump together a diverse set of erosional mechanisms). Refined, and more realistic, model predictions require advances in our quantitative understanding of erosion processes. Field-based investigation of bedrock incision processes is essential, but does not allow the investigator full control of critical variables. Controlled laboratory experiments have increasingly been used to explore fundamental aspects of the physics of river incision, to test existing models, and to guide their refinement. This research project at ASU includes flume experiments, data analysis, and theoretical development. The experiments will be designed to complement and extend previous flume studies. The primary controlling variables (flux and size distribution of sediment; channel slope; water discharge; and substrate hardness) will be varied in a systematic exploration of conditions, including the transition from bedload to suspended load transport. Bed morphology will be allowed to evolve naturally, and the critical feedbacks between bed morphology, fluid dynamics, sediment flux, and local erosion rate will be quantified. Based on preliminary experiments, field observations, and previous numerical studies, we formulate quantitative hypotheses that can and will be tested by direct measurement of erosion rate, bed topography, grain saltation trajectories, sediment transport rate, and fluid flow conditions, thus allowing refinement of current theory. The results from this research project will have important implications for basic science and a number of practical concerns of societal relevance. Advances in the understanding of the linkages between bedrock lithology, sediment characteristics and channel morphology are of potentially great value in solving applied problems of minimizing and mitigating for landuse impacts and restoring damaged riverine habitat and ecosystems. Engineering planning and management demand understanding of the processes that govern channel changes, including bed roughness and alluvial cover characteristics. A postdoctoral researcher, a graduate student and several undergraduates will receive invaluable training from this research project. Also, laboratory demonstrations will be developed for use in undergraduate courses and for public outreach events.

摘要： ASU 水槽研究？床载和悬载的磨损：实验研究？河流切入岩石在从实际到学术的各种问题中发挥着重要作用。 从大坝溢洪道设计，到河流管理规划，包括山区河流适宜水生栖息地的维护和河流恢复工作，到山区河流坡度、宽度和粗糙度的长期控制，对河流下切机制的定量理解深入摇滚是至关重要的，并且引起了广泛的兴趣。过去十年，人们在了解气候、地形、侵蚀和构造之间的相互作用方面取得了实质性进展；认识到河流切入岩石的核心作用是一个重要的见解。 然而，对基岩河道所发挥作用的探索主要是通过简化的河流动力模型（将多种侵蚀机制集中在一起的河流切割的通用规则集）完成的。精细且更现实的模型预测需要我们对侵蚀过程的定量理解取得进展。对基岩切割过程进行现场调查至关重要，但不允许调查人员完全控制关键变量。受控实验室实验越来越多地用于探索河流切割物理学的基本方面、测试现有模型并指导其改进。亚利桑那州立大学的这个研究项目包括水槽实验、数据分析和理论发展。这些实验旨在补充和扩展之前的水槽研究。主要控制变量（沉积物的通量和尺寸分布、河道坡度、排水量和基质硬度）将在对条件的系统探索中发生变化，包括从床质荷载到悬浮荷载运输的转变。河床形态将被允许自然演变，并且河床形态、流体动力学、沉积物通量和局部侵蚀率之间的关键反馈将被量化。 基于初步实验、现场观察和先前的数值研究，我们制定了定量假设，可以并且将通过直接测量侵蚀速率、河床地形、颗粒跃移轨迹、沉积物传输速率和流体流动条件来检验这些假设，从而可以细化当前的理论。该研究项目的结果将对基础科学和社会相关的许多实际问题产生重要影响。对基岩岩性、沉积物特征和河道形态之间联系的理解进展对于解决最小化和减轻土地利用影响以及恢复受损的河流栖息地和生态系统的应用问题具有潜在的巨大价值。工程规划和管理需要了解控制河道变化的过程，包括河床粗糙度和冲积层特征。一名博士后研究员、一名研究生和几名本科生将从该研究项目中获得宝贵的培训。此外，还将开发实验室演示用于本科课程和公共宣传活动。