BRIGE: Improving Resiliency of Coastal Systems using Bio-Mediated Soil Improvement & Promoting Women in Engineering

BRIGE：利用生物介导的土壤改良提高沿海系统的弹性

• 批准号: 1342207
• 负责人: Brina Montoya
• 金额: $ 17.5万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1342207&HistoricalAwards=false
• 关键词: BRIGE; Improving; Resiliency; Coastal; Systems

Background:Sand dunes are an invaluable geologic feature of our coastal environment. During Hurricane Sandy in 2012, coastal infrastructure protected by sand dunes had much less damage than the infrastructure that was not protected. The sand dunes naturally dampen the energy from the large wave action and prevent damage and erosion further inland. Large wave action and high sea levels erode the sandy soil that supports coastal lifelines, including bridges, highways, pipelines, and other utilities. Damage from these large storm events can result in severe property damage, loss of revenue, and large repair costs. Preventing the erosion of the sandy soil can improve the resiliency of these coastal systems by minimizing damage, reducing repair costs and allowing communities to recover quicker after the storm events. Current methods to reduce coastal erosion, such as hardened structures, increase down drift erosion and replace the natural environment with man-made infrastructure. Coastal sand dunes are also an integral part of the coastal ecology; therefore a process used to reinforce the erodible sandy soil should not disrupt the natural coastal ecology. Technical Description: The proposed project will provide a new soil improvement method to reinforce vulnerable lifelines in coastal communities. Applying MICP treatment methods to coastal sand dunes will require assessing the improved soil properties under new loading conditions and evaluating the effect the treatment process has on the surrounding ecology; hence, advancing the knowledge of bio-mediated soil improvement.Microbial Induced Calcite Precipitation (MICP) has the potential to reinforce coastal sand dunes while preserving the natural ecology of the dunes. MICP utilizes urea hydrolysis with calcium chloride as the chemical reaction to increase the alkalinity of the pore fluid and induce calcite precipitation. Sporosarcina pasteurii, a common alkalophilic soil bacterium, has a high urease activity and is used to facilitate the chemical reaction. The MICP process occurs naturally in situ cementing sand into sandstone; however, it can be harnessed and accelerated to be used as a natural soil improvement process. Assessing the ability for MICP to be used to protect coastal systems will be achieved by addressing the following objectives: 1) designing a MICP treatment process suitable for coastal soils, 2) evaluating the increase in shear strength and reduction of erosion potential, 3) addressing the potential effects (either adverse or beneficial) the MICP treatment process may have on the coastal ecology. Broader Significance and Importance:Over half of the global population lives near coastal communities, and these communities often struggle to rebound after large storm events. The proposed project is developed to advance bio-mediated soil improvement by developing new sustainable treatment methods for extreme loading conditions while minimizing the treatment?s impact on the local ecology. With the implementation of the treatment process developed within this project, lifelines will be able to resist the loading from large storm events while preserving the natural environment, which will improve the resiliency of the coastal infrastructure. In the broader context, the scientific advances from this project would also be applicable for liquefaction prevention, slope stability concerns, and roadway support.Broadening Participation of Underrepresented Groups in Engineering: In parallel with the bio-mediated soil improvement research, an outreach program is designed to promote female students to pursue a career in engineering. Society will benefit from an increase in female engineers by providing a diverse perspective to solve today?s challenges. The diversity-related goals of this project include increasing the interest of engineering among young female students and increasing the recruitment and retention female university students into graduate programs and academic careers. This goal will be met by exposing female students to different career paths in engineering and by providing female engineering role models the students can connect to during their elementary, middle school, and university education.This research has been funded through the Broadening Participation Research Initiation Grants in Engineering solicitation, which is part of the Broadening Participation in Engineering Program of the Engineering Education and Centers Division.

背景：沙丘是我们沿海环境的一个宝贵的地质特征。 2012年飓风桑迪期间，有沙丘保护的沿海基础设施受到的破坏要比没有保护的基础设施小得多。 沙丘自然地抑制了来自巨浪作用的能量，并防止进一步内陆的破坏和侵蚀。 大浪和高海平面侵蚀支撑沿海生命线的桑迪土壤，包括桥梁、高速公路、管道和其他公用设施。 这些大型风暴事件造成的损失可能导致严重的财产损失、收入损失和巨额维修费用。 防止桑迪土壤的侵蚀可以通过尽量减少损害、减少修复费用和使社区在风暴事件后更快地恢复来提高这些沿海系统的复原力。 目前减少海岸侵蚀的方法，如硬化结构，增加了漂流侵蚀，并以人造基础设施取代自然环境。 海岸沙丘也是海岸生态的一个组成部分;因此，用于加固易受侵蚀的桑迪土壤的过程不应破坏自然的海岸生态。 技术说明：拟议项目将提供一种新的土壤改良方法，以加强沿海社区脆弱的生命线。 将微生物诱导方解石沉淀（Microbial Induced Calcite Precipitation，MICP）处理方法应用于沿海沙丘，需要评估在新的负荷条件下改善的土壤性质，并评估处理过程对周围生态的影响;因此，推进生物介导土壤改良的知识。 MICP利用尿素与氯化钙的水解作为化学反应，以增加孔隙流体的碱度并诱导方解石沉淀。 巴氏孢子八叠球菌是一种常见的嗜碱性土壤细菌，具有较高的脲酶活性，可用于促进化学反应。 MICP过程自然发生在原地将沙子胶结成砂岩;然而，它可以被利用和加速，作为一种自然的土壤改良过程。 通过解决以下目标来评估MICP用于保护沿海系统的能力：1）设计适合沿海土壤的MICP处理过程，2）评估剪切强度的增加和侵蚀潜力的减少，3）解决MICP处理过程可能对沿海生态的潜在影响（不利或有利）。更广泛的意义和重要性：全球一半以上的人口居住在沿海社区附近，这些社区在大型风暴事件后往往难以恢复。 拟议项目的开发，以推进生物介导的土壤改良，开发新的可持续处理方法，极端负荷条件下，同时尽量减少治疗？对当地生态的影响。 随着该项目开发的处理工艺的实施，生命线将能够抵抗大风暴事件的负荷，同时保护自然环境，这将提高沿海基础设施的弹性。 在更广泛的背景下，该项目的科学进步也将适用于液化预防，边坡稳定性问题和道路支护。扩大代表性不足的群体在工程中的参与：在生物介导的土壤改良研究的同时，设计了一个推广计划，以促进女学生从事工程职业。 社会将受益于女性工程师的增加，提供了一个多样化的视角来解决今天的问题。的挑战。 该项目与多样性有关的目标包括提高年轻女学生对工程的兴趣，增加女大学生进入研究生课程和学术生涯的人数。 这一目标将通过让女学生接触工程学的不同职业道路和提供女性工程学榜样来实现，学生们可以在小学、中学和大学教育期间联系到这些榜样。这项研究是通过工程学教育和中心司工程学项目扩大参与研究启动赠款征集资助的。