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.

北半球近四分之一（包括加拿大一半的地产）的近四分之一受永久冻土的限制。从本质上讲，永久冻土是长期冷冻至少两年以下的地面。由于气候变化而导致的温度升高对多年冻土的强度和完整性有害。这种变暖的后果包括浅坡的不稳定性和近地表基础设施（例如管道）的变形，并将影响矿山填海框架中的景观设计。变暖使孔隙空间中的冰改变了水，这种水会导致部分冷冻材料中的内部孔隙水压增加。所提出的三轴系统将使我们能够通过受控变暖测量孔隙压力增加，从而量化了相对于温度曲线的随后强度降低。所需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冷冻并部分冷冻的土壤，以监测孔隙压力过渡变化，因为土壤融化。该系统将使我们能够编译一个独特的实验数据库，以开发和校准能够预测冷冻土壤强度变化的数值模型。尽管三轴测试通常用于岩土工程中以测量土壤的强度，但它们很少用于理解冷冻和部分冷冻土壤中的有效应力。通过获取该系统，我们的研究小组将在三个重要的研究领域为加拿大北部发展做出重大和根本贡献的最前沿：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，从而为他们提供独特的技能，使他们扮演有影响力的未来角色。