CLIMA/Collaborative Research: Landslide Triggering of Thermally Sensitive Slopes due to Climate Change

气候变化减缓和适应民用基础设施研究奖(CLIMA)支持的研究重点是了解由于存在对温度敏感的土壤材料，即它们的强度和硬度随着温度变化而发生重大变化而导致历史上稳定的或缓慢蠕动的自然土坡发生灾难性滑坡的风险增加。鉴于目前温室气体排放量的增加以及与地球平均温度上升的联系，这一点很重要。对物理学家、地质学家和工程师来说，解释和预测滑坡的开始、进展和规模仍然是一个挑战。该项目推进了温度变化何时以及如何触发这些灾难性的、可能致命的事件的科学。这项研究特别针对观察到的少量天然材料在不同温度下的行为与经历温度变化的大型自然土坡的稳定性之间的联系。在此基础上，将探索通过使用碳纳米纤维降低天然土壤斜坡的热敏感度来提高其对气候变暖的适应能力的范围。最后，这项研究将进一步被用来制作本科教材，以演示土木工程研究和实践如何适应气候变化。这项研究探索了热土壤的多物理响应和与灾难性斜坡破坏的联系，区分了土壤的微观和宏观属性与其状态变化的作用。中心假设是，在较高的温度下，热机械软化是在温度敏感的斜坡上触发深层斜坡运动的主要机制。对热敏材料的缩尺斜坡进行一套热三轴试验和离心机试验，将弥合在单元水平上对土壤热机械行为的实验观察和现场观察到的斜坡破坏之间的现有差距。土工离心机内的专门气候室将使等温测试和受控温度增量能够在缩小比例的模型上模拟气候变暖，以捕捉全尺寸坡度的非线性和应力相关行为。研究结果将丰富和验证预测的、温度敏感的粘塑性本构模型。这些组合的数据集最终将允许评估在温度敏感的土坡中引起的不同变形和破坏机制的相对重要性。这些奖励将进一步用于告知和测试在微观尺度上针对材料的织物以增加热敏感斜坡对气候变暖的弹性的有效性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This CiviL Infrastructure research for climate change Mitigation and Adaptation (CLIMA) award supports research focused on understanding the risk of increased catastrophic landslides of historically stable or slowly creeping natural soil slopes due to the presence of soil materials that are thermally sensitive, i.e., they exhibit significant changes of strength and stiffness in response to a change of temperature. This is important in view of current and increased greenhouse gas emissions and the link to increases of the average planet temperature. Explaining, and hence predicting, the initiation, progression and size of landslides remains challenging for physicists, geologists and engineers. This project advances the science of when and how temperature changes could trigger these catastrophic, and potentially deadly, events. This research specifically targets the link between the observed behavior of small volumes of natural material at different temperatures and the stability of large natural soil slopes experiencing a temperature change. Building on this link, the scope to improve the resiliency of natural soil slopes to warming climates by reducing their thermal sensitivity using carbon nano fibers will be explored. Finally, the research will be further leveraged to produce undergraduate teaching materials to demonstrate how Civil Engineering research and practice can adapt to climatic changes. The research explores the multi-physics thermal soil response and link to catastrophic slope failures, distinguishing between the role of the soil’s micro and macroscopic properties versus a change to its state. The central hypothesis is that at higher temperatures thermomechanical softening is the dominant mechanism that triggers deep-seated slope movements in thermally sensitive slopes. A suite of thermal triaxial tests and centrifuge experiments on reduced scale slopes of thermally sensitive materials will bridge the existing gap between experimental observations of the thermomechanical behavior of soils at the element level and the observations of slope failures in the field. A specialized climate chamber within a geotechnical centrifuge will enable isothermal tests and controlled temperature increments to model climatic warming on a reduced scale model capturing the non-linear and stress dependent behavior of the full-scale slope. The results will enrich and validate predictive, thermally sensitive visco-plastic constitutive models. The combined datasets will ultimately allow the assessment of the relative importance of different deformation and failure mechanisms induced in a thermally sensitive soil slope. These will be further used to inform and test the effectiveness of targeting the material’s fabric at the microscale to increase the resiliency of thermally sensitive slopes to warming climates.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.