Geomechanical Properties of Muskeg (Peat)

马斯基格（泥炭）的地质力学特性

• 批准号: RGPIN-2014-04336
• 负责人: Hendry, Michael
• 金额: $ 1.75万
• 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: 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=679753
• 关键词: Geomechanical; Properties; Muskeg; Peat

Canada has more muskeg (peat) covered land than any other country in the world, covering 18% of the land area, primarily in northern areas of the country. The common view of muskeg in geotechnical engineering is that it should be avoided as a foundation material whenever possible. However, avoidance is not always an option, particularly for linear, continuous structures such as those required for roads, railways and pipelines. As resource and infrastructure development continues to expand, particularly in northern Canada, it is anticipated that the number of engineering projects involving peat will only increase. In northern Alberta, older infrastructure constructed over muskeg has been subjected to large increases in traffic over the past decade, and this has resulted in widespread and ongoing stability and settlement issues.**Muskeg forms by the process of terrestrialization. This process starts at the margins of a shallow body of water, and due to the acidity, anoxic conditions and temperature of the water, the decay of the plant material is slowed to a pace at which it begins to accumulate and fill in the lake. This results in a range of peat formations, depending on the type of accumulated plant material, the state of decay and the access to oxygen. Muskeg has been described as an "ordinary extraordinary material" (Hobbs 1986). This highlights the fact that peat exhibits similar traits and correlations between geotechnical engineering properties and classification properties as mineral (particulate) soils (and thus ordinary); but with values for these properties that are greatly different from mineral soils (thus extraordinary). One example of this is the strength of peat, which is remarkably high given its exceptionally high water content. Muskeg also demonstrates a high degree of variability spatially as well as between different formations within a single region. Due to its complex nature, muskeg foundations pose unique problems for construction and maintenance of infrastructure constructed on top of it.**Several important gaps in the understanding of the fundamental engineering properties of muskeg were identified during previous and current research conducted by the applicant. These gaps include 1) a quantification of the variability of muskeg properties, and the effect of this on the selection of muskeg properties for the construction and remediation of infrastructure; 2) a model for the time-dependent deformation behaviour of muskeg under embankment loading which results in the large settlements; and 3) a complete characterization of the anisotropic strength and stiffness properties of muskeg which are fundamental to the determination of the stability of muskeg foundations. The results of this research are expected to contribute to the safety and reliability of infrastructure in Canada, reduce construction cost by the better prediction of the properties of muskeg and a reduction of the maintenance requirements for the structures currently constructed on muskeg.

加拿大有更多的muskeg（泥炭）覆盖的土地比世界上任何其他国家，覆盖18%的土地面积，主要是在该国的北方地区。在岩土工程中，通常认为应尽可能避免将其用作地基材料。然而，避免使用并不总是一种选择，特别是对于公路、铁路和管道所需的线性连续结构。随着资源和基础设施开发的不断扩大，特别是在加拿大北方，预计涉及泥炭的工程项目数量只会增加。在北方阿尔伯塔，在过去十年中，修建在沼泽上的较旧基础设施的交通量大幅增加，这导致了广泛和持续的稳定性和定居问题。麝香草是由陆地化过程形成的。这个过程开始于浅水区的边缘，由于水的酸性，缺氧条件和温度，植物材料的腐烂速度减慢，开始积累并填充湖泊。这导致了一系列泥炭的形成，这取决于积累的植物材料的类型，腐烂的状态和氧气的获取。马斯克被描述为“普通的特殊材料”（Hobbs 1986）。这突出了一个事实，即泥炭表现出类似的特点和岩土工程性质和矿物（颗粒）土壤（因此普通）的分类属性之间的相关性;但这些属性的值与矿物土壤（因此非凡）有很大的不同。这方面的一个例子是泥炭的强度，由于其特别高的含水量，泥炭的强度非常高。马斯克还展示了空间上以及单个区域内不同地层之间的高度可变性。由于其复杂的性质，muskeg基础对建造和维护在其上的基础设施提出了独特的问题。在申请人进行的先前和当前研究期间，确定了对麝香的基本工程性质的理解中的几个重要差距。这些差距包括：1）量化沼泽特性的可变性，以及这对选择沼泽特性用于基础设施建设和修复的影响; 2）在路堤荷载下沼泽随时间变化的变形行为模型，该模型导致大沉降;以及3）对沼泽地的各向异性强度和刚度特性的完整表征，这是确定沼泽地基础的稳定性的基础。这项研究的结果，预计将有助于在加拿大的基础设施的安全性和可靠性，降低建设成本，更好地预测的性能的麝香和减少的维护要求，目前建造的结构上麝香。