Pore Pressure Response to Loading of Warm Permafrost

孔隙压力对温暖永久冻土荷载的响应

• 批准号: RGPIN-2018-04503
• 负责人: Sego, David
• 金额: $ 8.81万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749109
• 关键词: Pore; Pressure; Response; Loading; Warm

The research focuses on enhancing Canadian permafrost engineers' understanding of the factors that control both stability of shallow slopes and deformation behavior of near surface foundations in permafrost regions. The temperature of this near surface permafrost is gradually warming due to climate change, and this warming is impacting the strength and deformation behavior of this near surface permafrost. This warming can lead to detrimental behavior of these materials related to stability of slopes and deformation of foundations. The research will establish the controlling influence of internally generated pore water pressure in partially frozen soils on the strength and deformation of this warming permafrost. Climate change has its major impact on the near surface frozen material at and just beneath the permafrost table (below the active layer). The ice rich composition of this warm permafrost is a challenge for the design engineer when evaluating their stability. Significant amounts of unfrozen water at below freezing temperatures can exist in warm permafrost, and the amount of this water increases with a small increase in temperature. Warming allows ice to change phase in the pore space, and this water can result in increases in internal pore water pressures in the partially frozen material. These changing pore water pressures can reduce the effective stresses, thus leading to a decrease in the resistance to sliding of the warming permafrost. The research is focused on determining how these pore pressures can change and measuring these changes with both temperature and stress. Understanding how these pore pressures develop will allow use of the effectives stress principle in future analysis of warm permafrost. This concept has not been used to date because of a lack of being able to accurately predict the internal pore water pressures in partially frozen soils. Research will also be carried out on the behavior of the pore water pressure developed during advancement of the freezing front in soils. This is being undertaken to improve the profession's understanding of the fundamentals of frost heave and the impact of rate of freezing advancement that control the amount of heave.The research findings will reduce the near term and future costs of road and airport foundations, and foundations and stability of slopes adjacent to this infrastructure.

该研究的重点是提高加拿大永久冻土工程师的理解的因素，控制浅边坡的稳定性和近地表基础在永久冻土地区的变形行为。 由于气候变化，近地表多年冻土的温度正在逐渐变暖，这种变暖正在影响近地表多年冻土的强度和变形行为。 这种变暖可能导致这些材料的有害行为，这些材料与斜坡的稳定性和地基的变形有关。 本研究将探讨部分冻土内部孔隙水压力对暖化多年冻土强度与变形的控制作用。 气候变化对永久冻土层（活动层以下）及其下的近地表冻结物质有重大影响。 这种温暖的永久冻土富含冰的成分是设计工程师在评估其稳定性时的一个挑战。 温暖的永久冻土层中可能存在大量低于冰点温度的未冻结水，并且随着温度的小幅上升，这些水的数量也会增加。 升温使冰在孔隙空间中改变相态，并且这种水可以导致部分冻结材料中的内部孔隙水压力增加。这些变化的孔隙水压力可以降低有效应力，从而导致在变暖的冻土滑动阻力下降。研究的重点是确定这些孔隙压力如何变化，并测量这些变化与温度和应力。 了解这些孔隙压力的发展，将允许使用有效应力原则在未来的分析温暖的多年冻土。 由于不能准确预测部分冻土中的内部孔隙水压力，这一概念至今尚未得到应用。 还将对土壤中冻结前沿推进过程中产生的孔隙水压力的行为进行研究。 这项研究的目的，是加深业内人士对冻土隆起的基本原理，以及控制隆起量的冻结推进速度的影响的认识。研究结果将可减少道路和机场地基，以及邻近基础设施的斜坡的地基和稳定性的短期和未来成本。