Collaborative Research: Geotechnical Investigation of Bivalve-Sediment Interaction with regard to Bivalve Farms as a Self-sustained Scour Mitigation Method

冲刷是一个严重的问题，在世界各地的结构基础是在或毗邻自来水。例如，在美国，桥梁倒塌最常见的原因是桥墩周围的冲刷。先前的研究表明，双壳类群落通过不同的过程减少了局部侵蚀，并且双壳类具有对强水流的高电阻率。然而，关于双壳类群落对海底岩土参数的影响，目前存在着知识上的差距。这阻碍了双壳类养殖场作为一种潜在的自我维持的减轻冲刷方法的评估和发展。这项基础研究将通过使用现场和实验室测试来解决这一知识差距。通过这种方式，这项研究将代表着将双壳类养殖场作为一种缓解冲刷策略的关键一步，并推动了沿海环境中生物地球工程领域的发展。在这个项目的框架下，新的跨学科、国内和国际合作将被启动，多名研究生和本科生将从参与这个创造性的、跨学科的和国际项目中受益。该项目还将通过强调招收女学生和来自不同社会经济背景的学生，寻求增加岩土工程领域的多样性。该项目将测试以下工作假设：H1)双壳类动物群落的存在减少了当地的冲刷和侵蚀。H2)双壳类菌落形成适用于防冲刷设计的形态。H3)双壳类黏附蛋白增加泥沙强度，降低可蚀性。H4)双壳类从土壤表面移出的情况如下？块失败?对于单个双壳类，但对于双壳类群体的侵蚀问题变得无关紧要。这些假设将通过跨学科和多方法的方法进行检验，其中包括：(i)在弗吉尼亚州和北卡罗来纳州的两个双壳贝群落地点进行实地调查，（ii）对双壳贝群落形态和流动电阻率与现代冲刷防护设计进行分析比较，并进行实验室测试，调查（iii）将双壳贝粘附蛋白与沉积物混合导致的沉积物强度和可蚀性的变化，以及（iv）双壳贝移动过程中的土壤破坏行为。该研究为水下环境生物岩土工程和冲刷防护开辟了新的方向。在较窄的范围内，该项目将提供信息，并解决与多学科和研究界（岩土工程、生物学、生态学、环境工程、水产养殖开发商）相关的知识差距。它将通过提供一种新的岩土技术视角，补充现有的双壳类动物栖息地特征及其在风暴事件期间在海岸保护中的作用的努力。它还将使人们对双壳类动物的移位过程有新的认识。为了最好地了解pi，贻贝粘附蛋白将首次进行测试，以评估它们对土壤力学特性的影响。研究结果为土壤临时改良的可持续发展提供了新的方向。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Scour is a serious problem throughout the world where structural foundations are in or adjacent to running water. For example, the most common cause for bridge failures in the U.S. is scour around bridge piers. Previous studies have suggested that bivalve colonies reduce local erosion through different processes, and that bivalves feature a high resistivity to strong flow. However, there exists a current gap in knowledge regarding the impact of bivalve colonies on geotechnical seabed parameters. This hampers the assessment and development of bivalve farms as a potentially self-sustained scour mitigation method. This fundamental study will address this gap in knowledge by use of field and laboratory testing. In this way, the study will represent a crucial step towards the use of bivalve farms as a scour mitigation strategy, as well as advance the field of bio-geo-engineering in coastal environments. In the framework of this project, new interdisciplinary, domestic and international collaborations will be initiated, and multiple graduate and undergraduate students will benefit from participation in this creative, interdisciplinary and international project. The project will also seek to increase diversity in the field of geotechnical engineering by emphasizing the recruitment of female students and students from diverse socioeconomic backgrounds.The project will test the following working hypotheses: H1) The presence of bivalve colonies reduces local scour and erosion. H2) Bivalve colonies form morphologies applicable to scour protection design. H3) Bivalve adhesive protein increases sediment strength and decreases erodibility. H4) Bivalve dislodgement from soil surfaces occurs as ?block failure? for single bivalves, but becomes irrelevant for erosion issues in the case of bivalve groups. These hypotheses will be tested through an interdisciplinary and multi-method approach featuring: (i) field investigations at two bivalve colony locations in Virginia and North Carolina, (ii) an analytic comparison of bivalve colony morphology and flow resistivity to modern scour protection designs, and laboratory tests investigating (iii) the change of sediment strength and erodibility resulting from mixing bivalve adhesive protein with sediment and (iv) soil failure behavior during bivalve dislodgement. The study may pave the way for a new direction in bio-inspired geotechnical engineering in submerged environments, and scour protection. In a narrower focus, the project will deliver information, and address knowledge gaps relevant for multiple disciplines and research communities (geotechnical engineering, biology, ecology, environmental engineering, aquaculture developers). It will complement existing efforts of characterizing bivalve habitats and their role in coastal protection during storm events by providing a novel geotechnical perspective. It will also enable new insights into the process of bivalve dislodgement. To the best knowledge of the PIs, mussel adhesive proteins will be tested for the first time to evaluate their impact on soil mechanical properties. The results may offer a new direction in temporary soil improvement in a sustainable manner.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.