Microbially-Induced Cementation of Sands by Denitrification

通过反硝化作用微生物诱导沙子胶结

• 批准号: 0856801
• 负责人: Edward Kavazanjian
• 金额: $ 33.01万
• 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: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0856801&HistoricalAwards=false
• 关键词: Microbially; Induced; Cementation; Sands; Denitrification

The research team will investigate the use of oxidation of organic compounds by denitrifying bacteria (?denitrification?) to induce carbonate cementation in sand. Microbially induced carbonate precipitation (MICP) offers the promise of a sustainable, non-disruptive and energy efficient engineering solution to a variety of important infrastructure development and geologic hazard mitigation problems, including remediation of liquefaction potential, improving foundation bearing capacity, and reducing (or even eliminating) excavation and tunnel support requirements. MICP through ureolysis is being investigated by several research groups in the U.S. and abroad. However, denitrification is potentially superior to ureolysis as a MICP process in that denitrifying bacteria are ubiquitous in the subsurface and the process works under anaerobic conditions, e.g. below the water table, while ureolysis requires oxygenation. Denitrifying bacteria and nutrients will be introduced into a laboratory soil column with pore water containing calcium carbonate in solution. Carbonate precipitation will be monitored by mass balance measurement of calcium concentrations in the pore fluid and the development of cementation will be monitored by shear wave velocity measurements in the soil column. These column experiments will be used to refine a biogeochemical model for denitrification, establish an optimal nutrient mix for denitrification, and establish precipitation and cementation rates for MICP by denitrification. Triaxial and simple shear tests on specimens from the column experiments will be used to evaluate the relationship between the amount of MICP and changes in the strength, stiffness, and liquefaction potential of the specimens. The proposed research has the potential to transform geotechnical practice, not only by development of a new, sustainable approach to ground improvement but also by advancing the emerging field of biogeotechnical engineering. This work is a continuation of work initiated under a National Science Foundation Small Grant for Exploratory Research (SGER).

该研究小组将调查使用氧化有机化合物的细菌（？脱氮作用？）以诱导砂中的碳酸盐胶结。 微生物诱导碳酸盐沉淀（MICP）为各种重要的基础设施开发和地质灾害缓解问题提供了可持续，非破坏性和节能的工程解决方案，包括液化潜力的补救，提高地基承载力，以及减少（甚至消除）开挖和隧道支护要求。 美国和国外的几个研究小组正在研究通过尿素分解的MICP。 然而，反硝化潜在地上级于作为MICP过程的尿素分解，因为反硝化细菌在地下普遍存在并且该过程在厌氧条件下（例如在地下水位以下）起作用，而尿素分解需要氧合。将反硝化细菌和营养物引入实验室土壤柱中，其中孔隙水溶液中含有碳酸钙。 碳酸盐沉淀将通过孔隙流体中钙浓度的质量平衡测量进行监测，胶结作用的发展将通过土柱中的剪切波速度测量进行监测。这些柱实验将用于完善反硝化的生物地球化学模型，建立反硝化的最佳营养混合物，并通过反硝化建立MICP的沉淀和胶结速率。 将使用柱试验中的样本进行三轴和简单剪切试验，以评估MICP量与样本强度、刚度和液化潜力变化之间的关系。 拟议的研究有可能改变岩土工程实践，不仅通过开发一种新的，可持续的地基加固方法，而且通过推进新兴的岩土工程领域。 这项工作是国家科学基金会探索性研究小额资助（SGER）下启动的工作的延续。