CAREER: Mechanics of Post-Wildfire Debris Flow and Transport

该学院早期职业发展（Career）奖旨在解决野火后泥石流对民用基础设施的破坏性影响。气候变化导致野火增加，对社区和自然环境构成多重危害威胁。在山火之后，被烧过的伤疤上的土壤变得防水，导致雨水径流冲下山坡，侵蚀土壤，带着沉重的巨石和碎片。迫切需要评估野火后的泥石流和运输，以保护社区的福利和繁荣，以及加州和美国的自然资源。该奖项旨在开发泥石流冲击力的新方法和模型，从而为受影响的民用基础设施提供更好的设计和改造策略。该项目支持代表性不足的高中生、本科生和研究生的教育，并激励他们追求跨学科和STEM主题。该项目连接了利益相关者，如加州地质调查局（CGS）和烧毁地区应急响应（BAER）的土壤科学家，他们渴望用最新的研究成果更新他们的一维风险评估模型。在这个项目中，学生们与CGS工程师一起度过了一段时间，并与BAER团队进行了交流，他们有机会以定量的形式收集野火后泥石流位置、当地土壤性质、天气和基础设施损坏的实地勘测数据，以及专家的想法、建议和关注。该项目的成果将显著提高烧伤地区以下社区的安全性，以及民用基础设施抵御自然灾害的能力。该项目包括一个综合研究和教育计划，通过使用耦合离散元素模型和物质点法对野火后泥石流、运输和对民用基础设施和建筑物的影响进行基本的、跨尺度的微观到宏观评估，建立紧急和急需的程序，以评估野火后泥石流对社区的影响。新的基于物理的水-空气-颗粒混合物流变学被整合到泥石流下坡速度与不同初始条件下混合物成分显著变化之间的一般相关性中。对民用基础设施的影响将进行评估和分类，以制定系统的缓解策略、结构加强、新的设计规范和早期预警系统。研究成果将确保高风险野火地区面临不利气候变化的弹性土木结构。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) award addresses devastating impacts of post-wildfire debris flows on civil infrastructure. Climate change has led to an increase in wildfires, posing multi-hazard threats to communities and natural environments. After wildfires, soil on burned scars becomes water repellent, which causes rainwater runoff to rush down hills and erode soil, carrying heavy boulders and debris. There is an urgent need to evaluate post-wildfire debris flow and transport to protect communities’ welfare and prosperity, and natural resources in California and the United States. This award aims to develop novel methodologies and models of debris flow impact forces that will lead to better design and retrofit strategies for impacted civil infrastructure. The project supports the education of underrepresented high-school, undergraduate, and graduate students and motivates them to pursue interdisciplinary and STEM topics. This project connects stakeholders, such as soil scientists at the California Geological Survey (CGS) and Burned Area Emergency Response (BAER), eager to update their one-dimensional risk assessment models with the latest research findings. While students on this project spend time with CGS engineers and communicate with BAER teams, they have an opportunity to collect field reconnaissance data on post-wildfire mudflows location, local soil properties, weather, and infrastructure damage in quantitative forms, as well as thoughts, recommendations, and concerns from experts. Results from this project will significantly improve the safety of communities below burned scars, as well as the resilience of civil infrastructure against natural hazards.This project includes an integrated research and education plan that establishes urgently and critically needed procedures for assessing post-wildfire debris flow effects on communities through a fundamental, across-scale micro-to-macro evaluation of post-wildfire debris flow, transport, and impacts on civil infrastructure and buildings using coupled Discrete Element Model and Material Point Method. Novel physics-based rheology of water-air-particle mixes is integrated into general correlations between mudflow downhill velocity and significant changes in mixture composition related to various initial conditions. Impacts on civil infrastructure will be assessed and categorized to develop systematic approaches to mitigation strategies, structure strengthening, new design codes, and early warning systems. Research outcomes will secure resilient civil structures facing adverse climate change in high-risk wildfire areas.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.