Climate Control Triaxial System for Strength Assessment of Frozen and Partially Frozen Soils

用于冻结和部分冻结土壤强度评估的气候控制三轴系统

• 批准号: RTI-2020-00127
• 负责人: Beier, Nicholas
• 金额: $ 10.93万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=693739
• 关键词: Climate; Control; Triaxial; System; Strength

Nearly a quarter of the northern hemisphere, including half of Canada's landmass, is underlain by permafrost. Essentially, permafrost is ground that remains perennially frozen for at least two years below zero degrees centigrade. Rises in temperature due to climate change have detrimental impacts on the strength and integrity of permafrost. The ramifications of this warming include increasing instability of shallow slopes and deformation of near-surface infrastructures, such as pipelines, and will impact landscape design in mine reclamation framework. Warming allows ice in the pore space to change phase to water, and this water can result in increases in internal pore water pressures in the partially frozen material. The proposed triaxial system will enable us to measure pore pressure increase with controlled warming and therefore quantify the subsequent strength reduction relative to temperature profiles. The requested state-of-the-art environmental triaxial testing system is capable of testing frozen and partially frozen soil under controlled temperature conditions to monitor the pore pressure transitional changes as frozen soil thaws. This system will allow us to compile a unique experimental database to develop and calibrate numerical models capable of predicting the change in the strength of frozen soils as it thaws. Although triaxial tests are routinely used in geotechnical engineering to measure strength of soils, they are rarely utilized to understand effective stresses in frozen and partially frozen soils. By acquiring this system, our research group would be at the forefront of making significant and fundamental contributions to Canada's northern development in three key research areas with strong support: mining waste management, construction, and railway industries. Furthermore, it will help create an edge in our HQP training, providing them with a unique skillset to place them in impactful future roles.

将近四分之一的北方，包括加拿大一半的陆地，都被永久冻土覆盖。从本质上讲，永久冻土是指在零下至少两年的时间里保持永久冻结的地面。气候变化导致的温度上升对永久冻土的强度和完整性产生了不利影响。这种变暖的后果包括增加浅边坡的不稳定性和近地表基础设施（如管道）的变形，并将影响矿山复垦框架中的景观设计。升温允许孔隙空间中的冰相变为水，并且这种水可导致部分冻结材料中的内部孔隙水压力增加。拟议的三轴系统将使我们能够测量孔隙压力增加与控制升温，因此量化随后的强度降低相对于温度剖面。所要求的最先进的环境三轴测试系统能够在受控温度条件下测试冻结和部分冻结土壤，以监测冻土解冻时孔隙压力的过渡变化。该系统将使我们能够编制一个独特的实验数据库，以开发和校准能够预测冻土强度变化的数值模型，因为它解冻。虽然三轴试验在岩土工程中经常用于测量土的强度，但很少用于了解冻结和部分冻结土的有效应力。通过收购该系统，我们的研究小组将在三个关键研究领域为加拿大北方的发展做出重大和根本性的贡献，并得到强有力的支持：采矿废物管理，建筑和铁路行业。此外，它将有助于在我们的HQP培训中创造优势，为他们提供独特的技能，使他们能够在未来发挥重要作用。