An investigation into open-system pingos in Canada as an analogue to drift-filled hollows in London

对加拿大开放系统 pingos 的调查，将其与伦敦充满漂流的空洞进行类比

• 批准号: NE/T013605/1
• 负责人: James Lawrence
• 金额: $ 1.34万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FT013605%2F1
• 关键词: investigation; into; open; system; pingos

EPSRC : Jennifer Scoular : EP/L016826/1A major hazard to engineering projects in London are geological features known as drift-filled hollows (DFHs). They are typically cone-shaped depressions in the bedrock filled with sand and gravel. DFHs can be up to 75 m deep and 90 to 475 m wide. They have been encountered on many small- and large-scale engineering projects in London, including the Thames Tideway Lee Tunnel, Crossrail, the Thames Water Ring Main and Battersea Power Station construction. These DFHs often contain water, therefore leading to water ingress whilst tunnelling as well as uneven settlement. The distribution of these features across London is poorly understood, due to their locations only being discovered during engineering projects.Engineers in London do not fully understand how these features formed. One hypothesis is that these features formed during historic glacial periods as pingos. Pingos are dome shaped mounds in cold regions characterised by permafrost. The dome shape is formed by an ice core, which is overlain with soil. The hypothesis is that, when these features melted in London, they were scoured out by rivers fed by glacial meltwater forming the DFHs we observe today. Regions where we can observe modern pingos is the Northwest Territories and Yukon territory of Canada.We propose both a fieldwork and remote sensing approach to test this hypothesis. Firstly, a direct inspection of pingo growth and characteristics of active pingos, followed by inspections of those that have collapsed. This will enable us to better understand if they could have formed in London in the past if the collapsed pingos in Canada share any characteristics with DFHs in London. Secondly, we will use remote sensing data including aerial photography, satellite imagery and digital elevation models, to make a digital map of the location of pingos in the Arctic. The locations may provide clues on factors that effect where they form, including water source for the ice and the type of soil they form under.From these observations, we aim to be able to conclude whether DFHs in London could have formed as pingos and if so, what factors affect their location to improve our knowledge of where to find them in London. With a major tunnelling project currently ongoing in London, the Thames Tideway Tunnel, also known as London's 'super-sewer', knowledge about the location of these hazardous features is of great importance.

EPSRC：Jennifer Scoular：EP/L016826/1伦敦工程项目的一个主要危险是被称为漂移填充空洞（DFH）的地质特征。它们通常是基岩中的锥形凹陷，充满沙子和砾石。DFH可达75米深，90至475米宽。他们在伦敦的许多小型和大型工程项目中遇到过，包括泰晤士潮汐隧道、横贯铁路、泰晤士水环干线和巴特西发电站建设。这些DFH通常含有水，因此导致隧道施工时进水以及不均匀沉降。这些特征在整个伦敦的分布情况知之甚少，因为它们的位置只在工程项目中被发现。伦敦的工程师们并不完全了解这些特征是如何形成的。一种假设是，这些特征在历史冰川时期形成为冰丘。冰丘是以永久冻土为特征的寒冷地区的圆顶状土丘。圆顶的形状是由冰芯形成的，冰芯上覆盖着土壤。假设是，当这些特征在伦敦融化时，它们被冰川融水注入的河流冲刷掉，形成了我们今天观察到的DFH。我们可以观察到现代冰丘的地区是加拿大的西北地区和育空地区。我们提出了一个实地调查和遥感方法来检验这一假设。首先，直接检查冰丘的生长和活动冰丘的特征，然后检查那些已经倒塌的冰丘。这将使我们能够更好地了解，如果他们可能已经形成在伦敦在过去，如果在加拿大的崩溃冰丘共享任何特征与DFH在伦敦。其次，我们将利用遥感数据，包括航空摄影，卫星图像和数字高程模型，使在北极冰丘的位置的数字地图。这些位置可能会提供影响它们形成的因素的线索，包括冰的水源和它们形成的土壤类型。从这些观测结果中，我们的目标是能够得出结论，伦敦的DFH是否可能形成为冰丘，如果是这样，是什么因素影响它们的位置，以提高我们在伦敦的知识。由于目前在伦敦正在进行一项大型隧道工程，即泰晤士潮汐隧道，也被称为伦敦的“超级下水道”，了解这些危险特征的位置非常重要。