CAREER: Decoding The Spatiotemporal Evolution of Soil Gradation under Severe Loadings: A New Paradigm for Stability Assessment of Critical Geo-Structures

职业：解码严重荷载下土壤级配的时空演化：关键地质结构稳定性评估的新范式

• 批准号: 2237332
• 负责人: Yida Zhang
• 金额: $ 59.99万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2028-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2237332&HistoricalAwards=false
• 关键词: CAREER; Decoding; Spatiotemporal; Evolution; Soil

This Faculty Early Career Development (CAREER) award will support research focused on the fundamental understanding of the grain-size evolution of granular soils under severe loadings and the development of new methodologies for stability and serviceability assessment of critical geo-structures. The grain size of soil constantly changes due to natural forces and human manipulation. Unwanted changes in gradation, such as the progressive breakdown of the load-bearing soil in embankments and tailings dams, can cause excessive deformation and threaten the safety of the structure over its extended service life. This research project will identify the principles that control the collective breakage of granular soils, enabling the development of new computational tools for predicting the spatial and temporal evolution of soil gradation. This will ultimately facilitate better engineering of large geostructures against extreme loading and aging. The research will also be closely integrated with an education effort aimed at equipping graduate students with the necessary toolkits for adapting geo-structures to climate change, promoting geotechnical undergraduate retention and research, and engage first-generation pre-college students in civil engineering projects.Specifically, this research project will: (1) examine the role of self-organization in grain breakage under quasi-static loading, (2) investigate the chain of micro events leading to the emergent creep of crushable soils, (3) quantify the mechanical and hydraulic behaviors of granular soils undergoing gradation shifting, (4) assess the short- and long-term stabilities of one of the world’s tallest tailings dams using the new gradation-enriched modeling paradigm. The following scientific questions will be addressed: (1) are there simple universal rules governing the crushing dynamics of arbitrarily graded granular materials?; (2) how do grains collectively break over time?; (3) can the critical-state behavior and the grain-size dynamics of sands be described using a unified constitutive theory?; (4) does the slow breakdown and creep of granular soils pose a safety threat for tall dams? The research outcomes will be useful for solving a broad class of geotechnical and geoscience problems involving grain-size evolution. These include pile penetration in crushable soils, breakage and degradation of railway ballasts, and formation of fast-moving debris flows and lithospheric shear zones. This project will enable the PI to establish his long-term career in extreme geomechanics research to address pressing issues at the interface of infrastructure, energy, and environment sectors.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.

该学院早期职业发展（CAREER）奖将支持对重载下粒状土壤颗粒尺寸演变的基本理解以及关键地质结构稳定性和适用性评估新方法的开发的研究。由于自然力和人为操作，土壤不断发生变化，例如路堤和尾矿坝中承重土壤的逐渐破裂，可能会导致过度变形并威胁结构的安全。该研究项目将确定控制粒状土壤集体破碎的原理，从而开发新的计算工具来预测土壤级配的空间和时间演变，这最终将有助于更好地设计大型地质结构。该研究还将与教育工作紧密结合，旨在为研究生提供使地质结构适应气候变化所需的工具包，促进岩土工程本科生的保留和研究，并吸引第一代大学预科生的参与。具体来说，该研究项目将：（1）研究准静态载荷下自组织在谷物破碎中的作用，（2）研究导致可压碎土壤突然蠕变的微事件链， (3) 量化经历级配变化的粒状土壤的机械和水力行为，(4) 使用新的级配丰富模型评估世界上最高的尾矿坝之一的短期和长期稳定性将解决以下科学问题：（1）是否存在控制任意分级颗粒材料的破碎动力学的简单通用规则？（2）颗粒如何随着时间的推移而集体破碎？以及使用统一的本构理论来描述沙子的粒径动力学？；（4）颗粒土的缓慢分解和蠕变是否会对高大坝的安全构成威胁？这些包括可压碎土壤中的桩穿透、铁路道碴的破损和退化，以及快速移动的泥石流和岩石圈剪切带的形成。该项目将使 PI 能够建立自己的长期职业生涯。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。