Groundwater and Flood Risk in the London Rail Infrastructure Network: Building Resilience into Existing Masonry Infrastructure Assets

降雨量增加带来的环境危害对铁路运输基础设施所有者和运营商构成越来越大的风险，因为更频繁的恶劣天气事件增加了洪水造成的服务中断的程度和反复出现的情况，以及相关的地面条件问题。这是一个在事件发生期间和发生后立即出现的问题，因为服务中断，在某些极端情况下，线路需要恢复，运营商需要付出高昂的成本，例如2014年道利什线路坍塌后所需的恢复，当时Network Rail正在投资超过350亿GB的重建和改善工作(BBC新闻)。地下水波动和过高的地下水位带来的危险也引起了负责基础设施网络和资产的持续维护和弹性规划的人员的持续关注。对于基础设施运营商来说，观测到的湿润制度的变化和潜在的进一步变化带来了未知的风险，同样，那些在基础设施发展方面提供咨询服务的公司也发现有必要增加他们对这些危险和风险的了解，以便继续向客户提供相关建议。然而，就历史建筑而言，这些破坏性事件所涉及的物理过程尚未完全了解，此外，这些事件对网络弹性的长期影响尚未确定。虽然历史建筑由于其持续存在的性质，表现出对极端气候事件的韧性，但我们没有办法确定它们对特定严重条件的反应。实现这一点将能够通过分析此类事件的变化频率对长期复原力的影响，准确预测未来的风险。这一点尤其重要，因为行业确定需要建立网络的复原力；这只有在我们首先了解所需额外缓解投资工作的程度的情况下才能成功实现。该项目将使用伦敦大学学院现有的技能和知识来分析隧道、路堤和高架桥的历史基础设施组件在结构内的稳定性和移动方面对不断变化的地下水条件的反应，容忍度适用于形成边界条件的基础设施运行。根据这一历史基础设施资产的脆弱性，将对与气候变化有关的湿度制度波动进行量化。最后，使用网络维持其容量功能的能力得出的关键指标来衡量这种响应对网络弹性的影响。伦敦-伦敦地铁运输作为资产所有者，将列出资产中最令人担忧的危险和脆弱性的性质，因此应首先进行研究，作为初始调查的一部分。作为基础设施发展经济部门的主要贡献者，奥雅纳将确保所使用的方法和产生的产出适合更广泛的专业服务部门，从而使该方法的行业适用性最大化。该项目寻求通过制定关于未来基础设施管理战略的指导方针来解决这一问题，该指导方针旨在制定一种较长期的方法来维护铁路网内的遗产资产。指南将确定与这些结构中易腐烂和失效的脆弱性相关的关键机制。此外，它不仅将提出修复现有资产的方法，以应对这些脆弱性，而且还将对其进行改造，以此作为永久缓解未来风险的一种手段。通过这种增强的弹性可以内置到网络中，确保为当前的未来风险做好准备，减少其潜在影响。

The environmental hazard posed by increased precipitation presents an ever more significant risk for rail transport infrastructure owners and operators, as more frequent severe weather events increase the extent and recurrence of disruption to services through flooding and associated ground condition problems. This is an issue during and in the immediate aftermath of an event, as services are disrupted and in some extreme cases lines require reinstatement at significant cost to the operator, such as that required following the Dawlish line collapse in 2014 where Network Rail are investing upwards of £35 billion in re-instatement and improvement works (BBC News).The hazards posed by groundwater fluctuations and excessive groundwater levels also pose a continual concern for those responsible for the ongoing maintenance and resilience planning for infrastructure networks and assets. Observed changes and potential further alterations to wetting regimes present an unknown risk for infrastructure operators, and similarly those providing consultancy services within infrastructure development have identified a need to increase their knowledge of these hazards and risks in order to continue to provide relevant advice to their clients.The physical processes involved in these disruptive events are however not fully understood with respect to historic structures, and furthermore the long-term impact of these events on resilience of the network is yet to be determined. Whilst historic structures, by nature of their continued presence, show resilience to extreme climate events, we do not have a means of determining their response to conditions of specified severity. Achieving this would allow for accurate prediction of future risks, through analysis of the impact of changing frequency of such events on long-term resilience. This is especially important in light of the need identified by the industry to build resilience into the network; this can only be successfully achieved if we first understand the extent of additional mitigation investment work required.The project will analyse using the skills and knowledge available at UCL CEGE the response of the historic infrastructure components tunnels, embankments and viaducts to changing groundwater conditions in terms of stability and movement within the structure, with tolerance's applicable to infrastructure operation forming the boundary conditions. From this vulnerability of historic infrastructure assets linked to moisture regime fluctuations associated with climate change will be quantified. Finally assessment of the impact of this response on the network resilience is measured using key indicators derived from ability of network to maintain its capacity function. Transport for London-London Underground as the asset owner will set out the nature of the hazard and vulnerabilities within the asset that are of most concern, and hence should be studied first as part of this initial investigation. Arup, as a key contributor to the economic sector of infrastructure development will ensure the methods used and outputs generated are tailored to suit the wider professional services sector, and hence that industry applicability of the method is maximised.The project seeks to address this through production of guidelines on future infrastructure management strategies concerned with developing a longer-term approach to maintenance of heritage assets within the rail network. The guidelines will identify the key mechanisms associated with vulnerability to decay and failure in these structures. Further, it will propose methods for not only repairing existing assets as a response to these vulnerabilities, but also for retrofitting them as a means of permanently mitigating against future risks. Through this increased resilience can be built into the network, ensuring risks of the future are prepared for now, reducing their potential impact.