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Translating from Kangaroo Rat Burrows to Geotechnical Engineering by Uncovering Fundamental Processes

通过揭示基本过程从袋鼠洞穴转化为岩土工程

基本信息

批准号：
2049636
负责人：
Idil Akin
金额：
$ 64.06万
依托单位：
Washington State University
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=2049636&HistoricalAwards=false
关键词：
Translating Kangaroo Rat Burrows Geotechnical

项目摘要

This award supports research to understand the role of kangaroo rats' microbiome in constructing resilient structures in extreme desert environments and how this knowledge can be scaled up to human geotechnical structures in extreme environments. Kangaroo rats construct elaborate burrows over multiple years and occupy them for extended periods of time. The burrows remain open and stable in desert sand and survive the harsh desert conditions, with extreme daily and yearly relative humidity and temperature fluctuations and flash-flood events. This research tests the hypothesis that the burrow microbiome is determined by the microbial community in cheek pouches or feet of kangaroo rats and that biofilms formed in this microbiome (i.e., burrow biofilms) are crucial to burrow stability in stochastic, fluctuating desert environments. The fundamental understanding gained from this project could translate to the design of sustainable ground improvement techniques to be used in geotechnical engineering practice, particularly in locations prone to landslides and substrate collapse. The research will establish direct collaborations among researchers, graduate students, and undergraduate students in geotechnical and geoenvironmental engineering, bioengineering, and biology. The research will specifically test the hypotheses that (i) the suction stress characteristic curve of burrow-biofilm-enhanced desert soil is a non-monotonic function of saturation, due to water retention by both the soil and the biofilm, and contributes to effective stress regardless of the extreme fluctuations in humidity, saturation, and temperature, to maintain the stability of the burrows and (ii) biofilms reduce the hydraulic conductivity of burrow ceilings, and therefore prevent flooding of the burrows during storms. The experimental program will include growing the burrow biofilms in the laboratory and determining the strength of burrow-biofilm-enhanced soil over the entire range of saturation and after multiple wet/dry and heat/cool cycles. The research will also investigate how water retention by the cementing agent (i.e., burrow biofilm) contributes to suction stress to maintain burrow stability under extreme fluctuations in environmental conditions. This is important for establishing the mechanistic basis for stability in sandy soils in arid environments. In addition, the research will study how the hydraulic conductivity of desert sand changes with the addition of burrow biofilm. Results from this research will reveal how one of the most prolific ecosystem engineers digs complex, stable, and sustainable underground environments in desert sand and how an individual’s phenotype extends from their microbiome, to burrow site selection, and more broadly to landscape biogeomorphology.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.

该奖项支持研究了解袋鼠微生物组在极端沙漠环境中构建弹性结构的作用，以及如何将这些知识扩展到极端环境中的人类岩土结构。袋鼠鼠花费数年时间精心建造洞穴，并长期占据其中。洞穴在沙漠沙子中保持开放和稳定，并在恶劣的沙漠条件下生存，每天和每年的相对湿度和温度波动以及山洪事件都极端严重。这项研究检验了这样的假设：洞穴微生物组是由袋鼠大鼠颊囊或脚部的微生物群落决定的，并且该微生物组中形成的生物膜（即洞穴生物膜）对于随机、波动的沙漠环境中洞穴的稳定性至关重要。从该项目中获得的基本理解可以转化为可持续地面改良技术的设计，用于岩土工程实践，特别是在容易发生山体滑坡和基质塌陷的地方。该研究将在岩土工程和地球环境工程、生物工程和生物学领域的研究人员、研究生和本科生之间建立直接合作。该研究将具体测试以下假设：（i）由于土壤和生物膜的保水作用，洞穴生物膜增强的沙漠土壤的吸力特征曲线是饱和度的非单调函数，并且无论湿度、饱和度和温度如何极端波动，都有助于有效应力，以维持洞穴的稳定性；（ii）生物膜降低了沙漠土壤的导水率。洞穴天花板，因此可以防止暴风雨期间洞穴被洪水淹没。实验计划将包括在实验室中培养洞穴生物膜，并确定洞穴生物膜增强土壤在整个饱和度范围内以及经过多次湿/干和热/冷循环后的强度。该研究还将调查胶结剂（即洞穴生物膜）的保水如何有助于吸力，以在环境条件极端波动下保持洞穴稳定性。这对于建立干旱环境中沙土稳定性的力学基础非常重要。此外，该研究还将研究沙漠沙的水力传导率如何随着洞穴生物膜的添加而变化。这项研究的结果将揭示最多产的生态系统工程师之一如何在沙漠沙中挖掘复杂、稳定和可持续的地下环境，以及个体的表型如何从微生物群延伸到洞穴地点选择，更广泛地延伸到景观生物地貌学。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进行评估，被认为值得支持标准。