'Seeing inside flood embankments' - novel geophysical imaging approaches for assessing the health of safety-critical flood defence infrastructure

在英国的防洪和运河网络中有数千公里的土堤防，其中大部分正在老化，并且在应对极端天气事件时显示出越来越多的故障。这些堤坝的破坏可能会造成严重的社会和经济影响，包括破坏、财产损失，甚至生命损失。管理这些结构的传统方法严重依赖于巡视检查或遥感信息。然而，它们不能提供地下信息；相反，他们只是在失败开始时才发现，而到那时，采取补救措施往往为时已晚。该项目旨在开发新兴的非侵入性地球物理成像技术，作为快速评估安全关键挡水结构内部状况的一种手段。这些技术的优势在于，它们有可能提供详细的地下体积信息，例如，岩性、强度、空化和水分含量，从而极大地帮助这些结构的状态评估和早期失效预警。目的与目标该项目的总体目标是开发新的综合地球物理方法来评估防洪土方工程的状况。具体目标包括：-为快速（2D）表征和详细（3D）评估开发优化的调查设计解决方案。-联合解释地球物理和环境数据，以建立可靠的地面模型。-评估新的地球物理方法对一系列经综合模拟和实地试验验证的路堤内部侵蚀情景的敏感性。-知识交流和传播活动，在最终用户和学术界的利益相关者之间传播地球物理表征的良好实践。方法将研究地球物理技术的两个强互补的类别——地电学和地震学。地电测量对成分变化（特别是粘土含量）和地下水饱和度/质量变化很敏感，而地震测量可以提供地下地质力学特性变化（弹性刚度和密度）的信息。调查设计解决方案、地面模型开发和敏感性分析将结合计算机模拟、小规模实验室测试（连接电气、地震和其他物理特性）和现场规模试验进行。试验场地将由环境局提供。详细的实验设计和现场选址将是一个涉及学生、导师和CASE合作伙伴（环境局和RSK）的合作过程。

Project descriptionThere are many thousands of kilometres of earth embankments within the UK flood defence and canal networks, much of which is aging and displaying increasing levels of failure in response to extreme weather events. The failure of these embankments can have severe social and economic impacts in terms of disruption, damage to property, and even loss of life. Conventional approaches to managing these structures are heavily reliant on walkover inspections or remotely sensed information. However, they cannot provide subsurface information; instead they only detect failure once it has begun, by which time it is often too late to undertake remedial action.This project seeks to develop emerging non-invasive geophysical imaging technologies as a means of rapidly assessing the internal condition of safety critical water retaining structures. The advantage of these techniques is that they have the potential to provide detailed volumetric subsurface information related to, for example, lithology, strength, cavitation and moisture content - thereby greatly assisting in the condition assessment of these structures and early warning of failure.Aims & ObjectivesThe overarching objective of the project is to develop new integrated geophysical approaches for condition assessment of flood defence earthworks. Specific aims include:- Developing optimised survey design solutions for both rapid (2D) characterisation and detailed (3D) assessments.- Joint interpretation of geophysical and environmental data to develop robust ground models.- Assessment of the sensitivity of new geophysical approaches to a range of embankment internal erosion scenarios validated through synthetic modelling and field trials.- Knowledge exchange & dissemination activities to inform good-practice in geophysical characterisation amongst stakeholders in the end-user and academic communities.MethodsTwo strongly complementary classes of geophysical techniques will be investigated - geoelectrics and seismics. Geoelectrical measurements are sensitive to compositional variations (particularly clay content) and groundwater saturation/quality changes, whereas seismic measurements can provide information on geomechanical property variations (elastic stiffness and density) of the subsurface.Survey design solutions, ground model development and sensitivity analyses will be undertaken using a combination of computer based simulations, small-scale laboratory testing (linking electrical, seismic and other physical properties) and field-scale trials. Trial sites will be provided by the Environment Agency. Detailed experimental design and field site selection will be a collaborative process involving the student, supervisors and CASE partners (Environment Agency and RSK)