Abrasion by Bedload and Suspended Load: Experimental Study

翻译后摘要：亚利桑那州立大学水槽研究？推移质和悬移质泥沙磨损的试验研究？河流对岩石的下切作用在从实际到理论的各种问题中起着重要的作用。 从大坝溢洪道设计，河流管理规划，包括维护合适的水生栖息地在山区河流和河流恢复工作，对山区河流的坡度，宽度和粗糙度的长期控制，定量了解河流切割成岩石的力学是必不可少的，具有广泛的兴趣。在过去的十年里，在理解气候、地形、侵蚀和构造之间的相互作用方面取得了重大进展;认识到河流切入岩石的核心作用是一个关键的见解。 然而，对基岩河道所起作用的探索主要是用简化的水流动力模型（河流下切的通用规则集，将各种侵蚀机制集合在一起）来完成的。精细的，更现实的，模型预测需要我们的侵蚀过程的定量理解的进步。基岩切割过程的实地调查是必不可少的，但不允许调查人员完全控制关键变量。受控实验室实验已越来越多地用于探索河流下切物理学的基本方面，以测试现有的模型，并指导其完善。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。实验将被设计为补充和扩展以前的水槽研究。主要控制变量（通量和沉积物的粒度分布;通道坡度;水流量;和基底硬度）将在条件的系统探索中变化，包括从推移质到悬移质运输的过渡。床形态将被允许自然演变，床形态，流体动力学，沉积物通量和局部侵蚀速率之间的关键反馈将被量化。 基于初步的实验，现场观察，和以前的数值研究，我们制定了定量的假设，可以并将通过直接测量的侵蚀速率，河床地形，颗粒跃移轨迹，泥沙输运速率和流体流动条件进行测试，从而使目前的理论细化。该研究项目的结果将对基础科学和一些具有社会意义的实际问题产生重要影响。基岩岩性，沉积物特性和通道形态之间的联系的理解的进展是潜在的巨大价值，在解决应用问题，最大限度地减少和减轻土地利用的影响，恢复受损的河流栖息地和生态系统。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这个研究项目中获得宝贵的培训。此外，实验室示范将开发用于本科课程和公共宣传活动。

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.