特邀报告人：伊恩·汤恩德，英国皇家工程院院士，HRWallingford原技术总监

Speaker：Ian Townend, Fellow of Royal Academy of Engineering, the UK

题目：海岸工程脆弱性及恢复能力评价

Title：Assessing Coastal Defence Vulnerability and Resilience

 时间：2015年5月29日 10:45-11:15

Time：May 29th 2015 10:45 am -11:15 am

摘要

自2014年冬天风暴肆虐英国海岸以 来，天气类型、风暴云团对洪水和海防的 影响受到越来越多的关注。很显然，造成 灾害损失或防护失败的风暴未必与海岸带 防护体系设计的极端条件相一致，且之前 被风暴破坏过的防护体系很难能再一次抵 挡并不是特别极端的风暴侵袭。这提示我 们需要重新思考：怎样才能最好地保证在 工程设计中不但顾及极端条件下的海岸带 防护体系的易损性，同时也考虑每次风暴 之后海防的恢复能力。以英国西南海岸的 Dawlish城前海防作为研究实例，通过重建 海洋条件模拟了2014年冬天多个风暴过 程，阐述了此方法的可行性。研究结果表 明，维持适量的海滩面积可以有效地降低 损失。在设计理念中结合海滩动力学与海 滩修复可为海岸防护体系的可靠性提供更 加谨慎的思路。该研究不但提供了一个减 少不确定性的有效方法，而且通过考虑结 构的易损性以及体系的修复能力来定义整 个防护体系的恢复能力，能更好反映对气 候变化和政策规划的考虑。

Abstract

Following the storms that battered the UK coast in the winter of 2014, increased attention has been given to weather patterns, clustering of storms and the impact this has on flood and coastal defences. It became apparent that storms that caused damage or defence failure were not necessarily extreme events consistent with the design of the structures. Defences that had been weakened by previous storms failed in storms that were not particularly extreme. This has prompted a re-think of how best to ensure that the design encompasses not only the vulnerability of defences to extreme events but also the overall resilience, taking account of any post storm recovery. This talk will outline an approach that endeavours to develop such an approach and will be illustrated with a case study based on Dawlish on the South West coast of the UK. To illustrate the approach a case study will be presented for the coastal defences that front the town of Dawlish. There is some evidence from the Dawlish site that maintaining an adequate beach could have prevented much of the damage. It is also the case that by incorporating the dynamics of the beach and particularly beach recovery into the design process would have led to a more cautionary view of the structural reliability of the defences. Work is in-hand to see whether the conceptual framework outlined provides a useful method reducing this uncertainty. By considering structural vulnerability and system recoverability as a basis for defining system resilience, this also maps on well to considerations of climate change and policy planning.