Thermal-mechanical response of frozen clay soil and the impact on soil-structure interaction

冻粘土的热力响应及其对土-结构相互作用的影响

• 批准号: RGPIN-2017-05169
• 负责人: Li, Biao
• 金额: $ 1.46万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=657416
• 关键词: Thermal; mechanical; response; frozen; clay

In northern Canada, frozen clay soil is very abundant in permafrost regions, where new infrastructure needs are being created as a result of heightened demand for resources. Long term records indicate an on-going global warming has resulted in thawing of portions of the permafrost area, which leads to extensive settlement of the ground surface and causing damage to infrastructures. Understanding the behavior of frozen soil under thermal-mechanical impact is the fundamental of studying on the soil-structure interaction, which is of significant importance to the development of safe and economical designs of infrastructures in cold regions. Currently, very little theoretical work on thermally induced strength weakening in frozen clay soil can be found, and numerical simulation on the temperature-dependent failure behavior in frozen clay soil is not available. There remains a significant knowledge gap in terms of understanding the underlying mechanisms of thermally induced mechanical degradation (weakening) of frozen clay soil and how those affect the performance of infrastructures. Consequently, very few companies would like to take into account of thermally induced failure of frozen clay soil in their designs.******This research program is proposed to put a step toward solving thermally induced problems in frozen ground engineering. The long-term scope of this program is to study thermal-hydro-mechanical-chemical coupled processes in frozen clay soils and the impact on soil structure interaction. The short-term scope (in 5 years) of this program is aimed at investigating the physics of thermally induced weakening in water-saturated frozen clay soil and the impact on soil-structure interaction. It has three objectives: (1) to perform laboratory tests to measure mechanical properties of frozen clay soil at different temperatures (2) to propose theoretical models for temperature-dependent mechanical properties and use the models in a numerical simulation tool (3) to propose an approach to simulate the soil-structure interactions in permafrost area with consideration of the temperature increase in frozen clay soils. The completion of this 5-years research program is the first part of the program's long-term scope.******The proposed research program will enrich the development of soil mechanics in the discipline of temperature related topics. The deliverables from this proposed research program will promote the interests of engineers to proactively consider thermal-mechanical impacts on designs and operations of buried structures in permafrost regions. Once the thermal impact on such soil-structure interaction is understood, it will be possible to upgrade the regulations for the design of infrastructures to account for the thermal impact. It will be very beneficial for engineering projects such as pipeline construction and natural resource exploitation in Canadian's permafrost regions.**

在加拿大北部，冻土地区的冻土非常丰富，由于对资源的需求增加，那里正在创造新的基础设施需求。长期记录表明，持续的全球变暖已导致部分永久冻土区融化，这导致地面大面积下沉，并对基础设施造成破坏。了解冻土在热-力冲击作用下的行为是研究土-结构相互作用的基础，对于发展寒冷地区安全经济的基础设施设计具有重要意义。目前，关于冻土热致强度弱化的理论研究很少，对冻土的温度相关破坏行为的数值模拟也很少见。在了解冻结粘土的热致机械退化(弱化)的根本机制以及这些机制如何影响基础设施的性能方面，仍然存在着重大的知识差距。因此，很少有公司愿意在他们的设计中考虑到冻土的热引起的破坏。*这项研究计划是为了向解决冻土工程中的热引起的问题迈出一步。该计划的长期范围是研究冻结粘土中的热-水-力-化学耦合过程及其对土壤结构相互作用的影响。该计划的短期范围(5年内)旨在研究饱和水的冻结粘土中的热诱导弱化的物理过程及其对土-结构相互作用的影响。其目的有三：(1)进行室内试验，测量不同温度下冻土的力学性质；(2)提出冻土力学性质随温度变化的理论模型，并在数值模拟工具中使用这些模型；(3)提出一种考虑冻土温升的冻土区土-结构相互作用的模拟方法。这项为期5年的研究计划的完成是该计划长期范围的第一部分。*拟议的研究计划将丰富土力学在温度相关学科中的发展。这项拟议研究计划的成果将促进工程师主动考虑对永久冻土区埋藏结构的设计和运营的热机械影响的兴趣。一旦了解了这种土壤-结构相互作用的热影响，就有可能升级基础设施设计的法规，以考虑热影响。这将对加拿大永久冻土区的管道建设和自然资源开发等工程项目非常有利。**