ERI: Progressive Formation and Collapse Mechanisms of Sinkholes Caused by Defective Buried Pipes

ERI：埋地管道缺陷造成天坑的渐进形成和塌陷机制

• 批准号: 2301392
• 负责人: Fei Wang
• 金额: $ 20万
• 依托单位: Tarleton State University
• 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 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2301392&HistoricalAwards=false
• 关键词: ERI; Progressive; Formation; Collapse; Mechanisms

This Engineering Research Initiation (ERI) award supports research that aims to understand why and how sinkholes form above defective buried pipes. Sinkholes induced by defective buried pipes have become a substantial threat to community safety, resulting in fatalities, damage to buildings and infrastructure, and economic loss. However, the collapse mechanism of sinkholes above buried pipes remains unclear, making prediction of sinkhole collapses difficult. In this project, the research team will identify the most susceptible soil and water flow conditions around defective pipes leading to sinkhole initiation and develop models to predict their growth. Currently, the US has more than one million miles of pipes nearing the end of their service lives that pose a sinkhole risk to their communities. This project will expand our understanding of formation and collapse mechanisms of such sinkholes to provide predictive capabilities. The research will also be complemented by establishing a responsive and flexible educational and outreach program based on curriculum development and K-12 summer camps that can motivate young students to pursue their college education in STEM fields.The research goal of this project is to predict sinkholes caused by defective buried pipes based on understanding of progressive formation and collapse mechanisms. To achieve this goal, the objectives are to (i) identify critical hydrogeological parameters leading to initiation of soil internal erosion around defective pipes through soil erosion tests in the laboratory; (ii) model the time-dependent progressive evolution of sinkholes induced by defective buried pipes using a sinkhole simulator; and (iii) develop an analytical method to predict the collapse timing and size of sinkholes considering external loads based on time-dependent soil arching models. This project will test three hypotheses: (1) internal soil erosion around defective buried pipes initiates when the ratio of hole diameter to D85 (i.e., 85% percent fines) of soil infill surrounding the pipe reaches a threshold value related to the hydraulic gradient; (2) sinkholes in a submerged zone will be cone-shaped with an angle from the horizontal direction that equals to the surrounding soil friction angle; and 3) sinkholes above the submerged zone will be dome-shaped, and collapse of the dome will be exaggerated by external loads. This project will allow the PI to advance knowledge of the sinkhole formation and collapse around defective buried pipes and to lay a firm foundation for his long-term career focused on safety and sustainability of buried civil infrastructures.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.

该工程研究启动 (ERI) 奖项支持旨在了解缺陷埋地管道上方为何以及如何形成天坑的研究。有缺陷的埋地管道引起的污水坑已对社区安全构成重大威胁，导致人员死亡、建筑物和基础设施损坏以及经济损失。然而，埋地管道上方天坑塌陷的机制尚不清楚，这给天坑塌陷的预测带来了困难。在该项目中，研究团队将确定导致天坑形成的有缺陷的管道周围最容易受到影响的土壤和水流条件，并开发模型来预测其生长。目前，美国有超过一百万英里的管道即将达到使用寿命，对社区构成天坑风险。该项目将扩大我们对此类天坑形成和塌陷机制的理解，以提供预测能力。该研究还将通过建立基于课程开发和 K-12 夏令营的响应性和灵活的教育和外展计划来补充，该计划可以激励年轻学生在 STEM 领域继续接受大学教育。该项目的研究目标是基于对渐进形成和塌陷机制的理解，预测由有缺陷的埋管引起的天坑。为了实现这一目标，目标是 (i) 通过实验室土壤侵蚀测试确定导致缺陷管道周围土壤内部侵蚀的关键水文地质参数； (ii) 使用污水坑模拟器对由有缺陷的埋地管道引起的污水坑随时间的渐进演化进行建模； (iii) 开发一种分析方法，根据时间相关的土拱模型，考虑外部荷载，预测天坑的塌陷时间和尺寸。该项目将测试三个假设：（1）当管道周围填充土壤的孔径与D85（即85％细粉）的比率达到与水力梯度相关的阈值时，有缺陷的埋地管道周围的内部土壤侵蚀就会开始； (2) 淹没区的沉洞呈圆锥形，其与水平方向的夹角等于周围土壤的摩擦角； 3）淹没区上方的天坑将呈圆顶状，外部荷载会加剧圆顶的塌陷。该项目将使 PI 能够增进对有缺陷的埋地管道周围天坑形成和塌陷的了解，并为其专注于埋地土木基础设施的安全和可持续性的长期职业生涯奠定坚实的基础。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。