Collaborative Research: Hybrid Flow-Sediment-Structure Interaction Analysis of Extreme Scour due to Coastal Flooding

合作研究：沿海洪水造成的极端冲刷混合流-泥沙-构造相互作用分析

• 批准号: 2050808
• 负责人: Majid Ghayoomi
• 金额: $ 26.16万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2050808&HistoricalAwards=false
• 关键词: Collaborative; Research; Hybrid; Flow; Sediment

Foundation scour is one of the primary causes of structural damage in coastal communities during flooding events. This project will leverage state-of-the-art in wave flume physical modeling, geotechnical centrifuge modeling, and numerical simulation to answer a number of critical and open questions related to the interactions among extreme flood flow, soil, and structure which lead to scour and foundation failure—shifting the paradigm in the current understanding of key physical processes in flood-induced scouring process in complex urban setting. Enhancement of open-source multi-physics computational tool for coastal hazard mitigation will provide a strong multi-disciplinary modeling platform to the broader civil and coastal engineering research community. The new parameterization set for extreme scour-liquefaction resulted from the fundamental knowledge-gain will benefit region-scale nearshore morphodynamic modeling and the state of foundation design in flood-prone areas. The education and outreach efforts will broaden the participation at all levels including: (1) recruitment, retention, and education of underrepresented students in three collaborating institutions; (2) engaging science teachers in three coastal states with different urban settings and population, in coastal infrastructure and community resiliency training; and (3) enhancing the well-being of the coastal residents through changing the design and hazard mitigation protocols.This project will bridge the state-of-the-art in sediment transport and scour, unsaturated and saturated soil mechanics, and hydrodynamics of flood flow. This goal will be achieved by correlating the spatiotemporal variations of scouring and loading with the dynamics of shallow flood flows within complex urban setting and water hysteresis in unsaturated soils around and underneath surface structures. The research objectives of this project are to understand: (1) scouring patterns of single and array of structures, under various flow and soil states; (2) initiation and progression of foundation scouring in low fines content soils of varying properties (i.e., composition, relative density, initial water content); (3) soil-foundation interaction response under simultaneous wave action and hydraulically-induced excess pore pressure; (4) rocking response of shallow foundations in unsaturated ground; (5) enhancement of an open-source Eulerian two-phase modeling framework for a complete description of seabed stability and scour; and (6) incorporating an extended effective stress-based sub-model and a revised solver for slight water compressibility to simulate soil behavior in partially drained and unsaturated condition with high overburden. The long-term goal of this project is to create public-domain tools for reliable scour predictions of complex urban and non-urban settings, under extreme coastal flooding conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

地基冲刷是洪水期间沿海社区结构损坏的主要原因之一。该项目将利用最先进的波槽物理建模、岩土离心机建模和数值模拟来回答一些与极端洪水流、土壤和结构之间相互作用相关的关键和开放性问题，这些相互作用会导致冲刷和地基破坏，从而改变目前对复杂城市环境中洪水引起的冲刷过程关键物理过程的理解范式。增强沿海灾害缓解的开源多物理计算工具将为更广泛的土木和沿海工程研究界提供强大的多学科建模平台。由基础知识获得而产生的极端冲刷液化的新参数化集将有利于区域尺度近岸形态动力学建模和洪水易发地区的基础设计状况。教育和推广工作将扩大各个层面的参与，包括：(1) 在三个合作机构招募、保留和教育代表性不足的学生； (2) 让具有不同城市环境和人口的三个沿海州的科学教师参与沿海基础设施和社区复原力培训； (3) 通过改变设计和减灾方案来提高沿海居民的福祉。该项目将在泥沙输送和冲刷、非饱和和饱和土壤力学以及洪水流的流体动力学方面连接最先进的技术。这一目标将通过将冲刷和荷载的时空变化与复杂城市环境中浅层洪水流的动态以及地表结构周围和地下的不饱和土壤中的水滞现象相关联来实现。本项目的研究目标是了解：（1）单个结构和阵列结构在不同水流和土壤状态下的冲刷模式； (2) 不同性质（即成分、相对密度、初始含水量）的低细粉含量土壤中地基冲刷的开始和进展； (3)同时波浪作用和水力引起的超孔隙水压力下的土-地基相互作用响应； (4)非饱和地基浅基础的摇摆响应； (5) 增强开源欧拉两相建模框架，以完整描述海底稳定性和冲刷； (6) 结合扩展的基于有效应力的子模型和修正的轻微水压缩性求解器，以模拟部分排水和高覆盖层不饱和条件下的土壤行为。该项目的长期目标是创建公共领域工具，在极端沿海洪水条件下对复杂的城市和非城市环境进行可靠的冲刷预测。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。