Performance Evaluation of Critical Geosystems Using Multiscale Methods

世界各国依靠各种岩土基础设施进行防洪、蓄水和水力发电。这些关键的地质系统通常涉及与结构元素相互作用的多孔介质，例如溢洪道墙、与出水口工程相关的管道或支撑堤坝的相邻重力结构。在洪水期间的高水位下，或在没有明显触发事件的正常运行条件下，堤坝或堤坝可能会因内部侵蚀而崩溃。后者可归因于各种因素，包括现有树根的腐烂或入侵的野生动物活动，导致堤坝或堤坝内的局部空洞保持隐藏，直到地球结构的安全受到威胁。由于这些因素，全球每年因土质结构失效或损坏而造成的平均成本超过数十亿美元。在地球系统中，土壤退化和与侵蚀有关的破坏造成的负面影响并不局限于土壤结构。现有结构下面或附近的管道泄漏也会导致突然的、未被注意到的故障。 在加拿大，有几个地区容易发生洪水，这在很大程度上是由于水资源丰富和极端的季节性温度。人们对完整的土结构进行了广泛的研究，以研究管道、侵蚀和溢流的机理。然而，与土结构破坏机理的综合相关的研究在文献中非常少。 现有的工程工具和程序在模拟流水、土壤介质和嵌入结构之间的相互作用的动力学方面非常有限。为了解决这一问题，目前的工作将发展一个严格的多尺度方法，以提供尽可能多的信息，以合理可行的这一复杂的土壤-水-结构相互作用问题。这项发现赠款的主题是开发新的工程工具，利用离心机实验和多尺度建模方法评估极端条件下关键岩土结构的性能。这项研究计划的结果将帮助工程师和研究人员评估现有土坝和堤坝的安全性。它还将解释与埋在地表和地下结构附近的泄漏管道相关的土壤不稳定和破坏。 上述研究计划将包括在五年资助期内培训四名硕士和五名博士生以及五名暑期本科生。即将毕业的岩土工程师将对实验研究和复杂模型的重要性(和局限性)有一个平衡的看法，并将成为加拿大和国际科学界的真正财富。

Countries around the world rely on various geotechnical infrastructure for flood control, water storage and hydroelectric power generation. These critical geosystems typically involve a porous media interacting with structural elements such as spillway walls, conduits associated with outlet works or adjoining gravity structures supporting the embankment. The failure of levees, or embankment dams by internal erosion may occur under high water levels during flood events or under normal operating conditions without an apparent triggering event. The latter can be attributed to various factors including decay of existing tree roots or invasive wildlife activities that result in local voids within levees or embankment dams that remain concealed until the safety of the earth structure is jeopardized. The worldwide average cost of failed or damaged earthen structures due to these factors exceeds billions of dollars per year. The negative impact of soil deterioration and erosion-related failure in geosystems is not limited to earth structures. Leaking pipes under or near existing structures are also known to cause sudden and unnoticed failure. In Canada, several regions are prone to flooding due, in large part, to the abundance of water resources and the extremes in seasonal temperatures. Extensive research has been done on intact earth structures to study the mechanisms of piping, erosion, and overtopping. However, studies related to the synthesis of failure mechanisms of earth structures with either (a) local soil deterioration, or (b) embedded structural elements are very scarce in the literature. Current engineering tools and procedures are very limited in modeling the dynamics of the interaction between the flowing water, the soil media and embedded structures. To address this issue, the present work will develop a rigorous multiscale approach to provide as much information as reasonably feasible about this complex soil-water-structure interaction problem. The theme of this Discovery Grant relates to developing new engineering tools to assess the performance of critical geotechnical structures under extreme conditions using centrifuge experiments and multiscale modeling approaches. The outcome of this research program will help engineers and researchers to evaluate the safety of existing earth dams and levees. It will also explain the soil instability and failure associated with leaking pipes buried near surface and subsurface structures. The above research program will involve training of four Master and five Doctoral students in addition to five summer undergraduate students over the five year funding period. The graduating geotechnical engineers will have a balanced outlook on the importance (and limitations) of experimental research and sophisticated modelling, and will be a real asset to the scientific communities in Canada and internationally.