Geomechanical Properties of Muskeg (Peat)

加拿大泥炭覆盖的土地比世界上任何其他国家都多，占国土面积的18%，主要在该国的北部地区。在岩土工程中，人们普遍认为应尽可能避免将其作为地基材料。然而，避免并不总是一种选择，特别是对于公路、铁路和管道等所需的线性、连续结构。随着资源和基础设施开发的继续扩大，特别是在加拿大北部，预计涉及泥炭的工程项目的数量只会增加。在艾伯塔省北部，在过去十年中，在muskeg上建造的旧基础设施受到交通流量大幅增加的影响，这导致了广泛和持续的稳定和解决问题。**麝香是由陆地化过程形成的。这个过程始于浅水的边缘，由于水的酸性、缺氧条件和温度，植物材料的腐烂速度减慢到开始积聚并填满湖泊的速度。这就产生了一系列泥炭的形成，这取决于积累的植物材料的类型、腐烂的状态和获得氧气的途径。麝香被描述为一种“普通的非凡材料”（Hobbs 1986）。这突出了一个事实，即泥炭在岩土工程特性和矿物（颗粒）土壤（因此是普通土壤）的分类特性之间表现出类似的特征和相关性；但这些特性的价值与矿物土壤有很大不同（因此是非凡的）。其中一个例子是泥炭的强度，考虑到它的含水量非常高，它的强度非常高。Muskeg还证明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，麝香基给其上的基础设施的建设和维护带来了独特的问题。**在申请人之前和目前进行的研究中，发现了对麝香瓶基本工程特性理解方面的几个重要空白。这些差距包括1)对麝香属性可变性的量化，以及这对选择麝香属性用于基础设施建设和修复的影响；2)土体在路堤荷载作用下的随时间变形特性模型；3)完整地描述了麝香基的各向异性强度和刚度特性，这是确定麝香基稳定性的基础。这项研究的结果预计将有助于加拿大基础设施的安全性和可靠性，通过更好地预测muskeg的特性来降低建设成本，并减少目前在muskeg上建造的结构的维护要求。

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.