Field survey and characterization of southern Ontario tills and St. Lawrence Valley marine clays****

第四纪冰川沉积覆盖了安大略省南部的大部分地区和圣劳伦斯山谷，覆盖了冰川湖或海洋细粉。由于河流水流与河床和岸边沉积物的相互作用，切割成这些物质的河流显示出特殊的地貌行为。土木工程(如水坝、桥墩等)，旁边(公路、铁路等线性基础设施)或跨越(如桥梁等)这样的河流必须考虑到这些粘性沉积物的侵蚀，特别是在河流流量被建成的建筑物改变的情况下。目前，人们对这些物质的侵蚀门槛和侵蚀速度知之甚少，也不知道它们的地理分布以及不同地层和不同矿床之间的物质性质范围。这导致了水力、岩土、运输和结构工程项目的设计挑战和长期维护考虑，这可能会导致生命周期成本增加，并可能因意外侵蚀而失败。最近对许多已完成项目进行的侦察调查表明，在一些地方需要采取紧急干预措施，这些地点的侵蚀活动已造成人员安全问题，如果侵蚀在不久的将来继续下去，可能会造成环境和经济损失。拟议的研究将通过实地调查确定侵蚀过程的特征，并从收集的土壤样本中确定沉积物间和沉积物内材料的标准岩土参数的范围和变异性，从而加深对评估和预测冰川耕作和海洋粘土中已建建筑物的河流侵蚀过程所需的了解。该项目将帮助确定由于冰川耕作或海洋粘土的存在而存在潜在设计挑战的项目，从而使设计能够以较低的风险和较低的成本进行。增加的知识将提高专业知识和培训年轻工程师，同时咨询公司将能够更具竞争力地竞标，客户将以更低和更可预测的成本改善项目的长期管理。

Quaternary glacial deposition has covered much of southern Ontario with tills and the Saint Lawrence Valley with glaciolacustrine or marine fines. Rivers incised into these materials exhibit particular geomorphologic behavior due to the interaction of the river flows with the bed and bank sediments. Civil engineering works built either in (e.g. dams, bridge piers, etc.), beside (linear infrastructure such as roads, railways, etc.) or across (e.g. bridges, etc.) such rivers must consider the erosion of these cohesive sediments particularly where river flows are modified by built structures. There is currently very little knowledge about the threshold and rate of erosion of these materials, nor about their geographic distributions and the range of material properties between different strata and deposits. This leads to design challenges and long-term maintenance considerations for hydraulic, geotechnical, transportation and structural engineering projects that can result in increased lifecycle costs and the potential for failure due to unexpected erosion. Recent reconnaissance surveys conducted for many completed projects have indicated that urgent intervention was required at several locations where active erosion had caused safety issues for personnel and could cause environmental and economic losses if erosion were to continue in the near future. The proposed research will develop the improved understanding required to assess and predict erosion processes of rivers in glacial tills and marine clays for built structures by characterizing the erosion process from field surveys and determining, from collected soil samples, the range and variability of standard geotechnical parameters of the materials both inter and intra-deposits. This project will help identify projects with potential design challenges due to the presence of glacial tills or marine clays, allowing for designs with a lower risk and lower costs. The increased knowledge will improve expert knowledge and train young engineers, while consulting companies will be able to bid more competitively and clients will have improved long-term management of projects with lower and more predictable costs.****************