CAREER: From Pore to Pipe: A Multiscale Experimental and Numerical Study of Piping in Unsaturated Soil

这个教师早期职业发展（CAREER）奖将探讨土壤管道和非饱和土壤中的滑坡之间的关系。当流水侵蚀土壤，在地表下形成管道时，就会发生管涌。管涌是堤坝溃堤的主要原因之一，也是世界范围内土壤侵蚀的主要来源，并可能导致空洞和天坑的形成，从而可能破坏覆盖的基础设施。对管道的力学仍然知之甚少，阻碍了检测和监测管道的方法以及防止故障或在管道开始时进行维修的方法的发展。该项目将开发一个基于物理的框架，通过多尺度实验和数值模拟程序来评估土壤管道的发展，进展和后果。提高工程师检测和评估管道特征的能力，将提高民用基础设施对滑坡和天坑的复原力，并有助于减少农业用地退化和山坡土壤流失。这项研究将与教育和推广计划相结合，旨在提高传统上代表性不足的土木工程学生的兴趣和保留率。这将通过创建正式和非正式的教育活动来实现，包括为本科生和7 - 12年级学生提供的教育模块，以及一个由公民科学驱动的天坑和管道特征数据库。该项目还将创建一个新的课程，培养研究生有效地沟通他们的研究，以不同的观众。土壤管涌的过程涉及复杂的水力机械相互作用，发生在多个长度尺度。不同学科的研究人员已经研究了土壤管涌的不同方面，但需要一种趋同的研究方法来弥合目前的知识差距。该项目将通过确定控制非饱和土壤地下侵蚀的水力机械特性和相互作用来满足这一需求。X射线微CT成像将用于了解土壤微观结构如何影响侵蚀速率，并将进行大规模实验，以检查中尺度的管道进展和坍塌。无损地球物理成像将与吸力，水压和表面变形的测量相结合，以了解管道与周围土壤之间随着时间的推移的相互作用。这些实验将提供开发和验证土壤管涌及其对边坡稳定性影响的耦合水力机械模拟所需的数据。在这项研究中开发的分析框架将适用于许多其他管道相关的问题，在不同的学科。这个奖项反映了NSF的法定使命，并已被认为是值得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的支持。

This Faculty Early Career Development (CAREER) award will explore the relationship between soil piping and rainfall-induced landslides in unsaturated soils. Piping occurs when flowing water erodes soil forming a conduit, or pipe, below the ground surface. Piping is one of the leading causes of failures of levees and dams, a major source of soil erosion worldwide, and can lead to the development of voids and sinkholes that may damage overlying infrastructure. The mechanics of piping remain poorly understood, hindering the development of methods to detect and monitor piping and methods to prevent failure or repair piping once it has begun. This project will develop a physics-based framework for assessing the development, progression, and consequences of soil piping through a multiscale program of experiments and numerical simulations. Improving the ability of engineers to detect and evaluate piping features will increase the resiliency of civil infrastructure to landslides and sinkholes, and help to reduce degradation of agricultural land and soil loss in hillslopes. This research will be integrated with an education and outreach program that seeks to increase interest and retention among traditionally underrepresented students in civil engineering. This will be accomplished through the creation of formal and informal educational activities, including educational modules for undergraduate and 7th-12th grade students and a citizen science-driven database of sinkholes and piping features. This project will also create a new course to train graduate students to effectively communicate their research to diverse audiences.The process of soil piping involves complex hydro-mechanical interactions that occur across multiple length scales. Researchers in various disciplines have studied different aspects of soil piping, but there is a need for a convergent research approach to bridge the current knowledge gaps. This project will fill this need by identifying the hydro-mechanical properties and interactions that control subsurface erosion in unsaturated soils. X-ray micro-CT imaging will be used to understand how the soil microstructure influences erosion rates and large-scale experiments will be performed to examine pipe progression and collapse at the mesoscale. Non-destructive geophysical imaging will be integrated with measurements of suction, water pressure, and surface deformations to understand the interactions between the pipe and surrounding soil over time. These experiments will provide the data needed to develop and validate coupled hydro-mechanical simulations of soil piping and its influence on stability of slopes. The analysis framework developed in this study will be applicable to many other piping-related problems across a variety of disciplines.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.