CAREER: Spatial Quantification of Fundamental Mechanisms that Initiate Post-Wildfire Wetting-Induced Shallow Landslides

该学院早期职业发展（Career）奖将探索从野火中恢复的森林环境的动态变化如何随着时间的推移控制烧焦山坡的稳定性，防止潮湿引起的浅层滑坡。美国的野火管理战略已经从“扑灭野火”转变为“与野火共存”，即社区对野火的适应。野火后山体滑坡已被确定为严重的级联风险，影响社区对野火的适应，但基本的启动机制尚不清楚。目前还没有专门针对野火的方法来评估被烧毁的山坡的滑坡易感性。该项目将是开发野火特定框架的第一步，用于分析不同强度火灾和不同滑坡机制下山坡稳定性随时间、饱和度和森林利用实践的函数。这项研究将与一项教育计划相结合，旨在培养新一代工程师，使他们能够分析和减轻野火后山体滑坡的风险，向政策制定者提供信息，并促进有关此类风险的社区教育。本研究的主要研究目标是量化野火后环境中改变土壤力学和水文行为以及边坡稳定性的基本机制。据推测，基本机制受森林系统动力学（即树木损失、再生、灰分运动）的控制，它们协同控制吸力应力。为了实现主要研究目标，将实现以下具体目标：1)量化野火后吸力应力和森林系统动态随时间的变化；2)确定森林系统动力学成分与吸力应力相关的变化函数；3)使用概率方法评估野火后浅层滑坡的易感性。这将需要对野火后环境中的土壤行为进行多尺度调查。该研究计划包括测试从原子尺度到山坡尺度的土壤行为，并将允许多传感器数据融合。现场和实验室数据将与激光雷达扫描和航空照片的空间数据相结合。沿山坡吸力应力的空间变异性将以分布函数的形式呈现，并将作为概率边坡稳定性模型的输入，用于评估燃烧山坡的湿润诱发浅层滑坡敏感性。此外，还将通过水蒸气吸附等温线研究吸力应力的吸附分量对土壤持水曲线的依赖关系。这将提高我们对物理化学力对土壤机械行为的影响程度的理解。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 will explore how dynamic changes in a forest environment that is recovering from a wildfire control the stability of burnt hillslopes against wetting-induced shallow landslides over time. The US wildfire management strategy has changed from “fighting wildfires” to “living with wildfires,” which involves community adaptation to wildfires. Post-wildfire landslides have been identified as a serious cascading risk to community adaptation to wildfires, but the fundamental initiation mechanisms are not yet understood. There is currently no wildfire-specific approach to evaluating the landslide susceptibility of burned hillslopes. This project will be the first step toward developing a wildfire-specific framework for analyzing the stability of hillslopes as a function of time, saturation, and forest use practices for different intensity fires and different landslide mechanisms. The research will be integrated with an education program aiming to place a new generation of engineers in a position to analyze and alleviate the risk of post-wildfire landslides, inform the policy makers, and promote community education about such risks.The primary research objective of this study is to quantify the fundamental mechanisms that change mechanical and hydrologic soil behavior and therefore slope stability in post-wildfire environments. The fundamental mechanisms are hypothesized to be controlled by forest system dynamics (i.e., tree loss, regrowth, ash movement), that synergistically control suction stress. To achieve the primary research objective, the following specific objectives will be achieved: 1) quantify post-wildfire suction stress and forest system dynamics over time, 2) identify the change functions for the components of forest system dynamics in relation to suction stress, and 3) evaluate post-wildfire shallow landslide susceptibility using a probabilistic approach. This will require a multiscale investigation of soil behavior in post-wildfire environments. The research plan involves testing soil behavior from the atomic scale to the hillslope scale and will allow multi-sensor data fusion. Field and laboratory data will be combined with spatial data from LiDAR scans and aerial photographs. The spatial variability in suction stress along the hillslope will be presented as a distribution function and will be an input for a probabilistic slope stability model for evaluating the wetting-induced shallow landslide susceptibility of burned hillslopes. In addition, the dependency of the adsorptive component of suction stress on the soil water retention curve will be investigated through water vapor sorption isotherms. This will improve our understanding of the degree of physicochemical forces on mechanical soil behavior.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.