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Multiscale and probabilistic modelling of progressive slope failure

渐进式边坡破坏的多尺度和概率建模

基本信息

批准号：
EP/V028723/1
负责人：
Tao Zhao
金额：
$ 33.9万
依托单位：
Brunel University London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FV028723%2F1
关键词：
Multiscale probabilistic modelling progressive slope

项目摘要

In the UK and globally, the slope failures of various sizes are crucially affecting the sustainable development of resilient cities, as its occurrence can significantly threaten the populations, infrastructures, public services, and environment. For example, the British Geological Survey has estimated that 10% of slopes in the UK are classified as at moderate to significant landslide risk, with more than 7% of the main transport networks located in these areas. These slopes may fail during prolonged periods of wet weather or more intensive short duration rainfall events. To date, the public awareness of slope failure risk is high, but our understanding of its fundamental failure mechanism and countermeasures are still very limited. This is mainly due to the difficulties in analysing the multiscale responses and characterize the spatial inhomogeneity of material properties of slopes. Laboratory and numerical investigations with well-developed empirical models can explain the general features of some specific slope failure events but cannot be applied universally. Some challenging issues need to be addressed, such as i) How to develop reliable mathematical models with multiscale modelling capability to analyse the progressive failure of slopes? ii) How to address the spatial variabilities and uncertainties of real slopes, e.g. material property, fractures, fluid permeability? iii) How to accurately estimate the spreading of landslide and its impact on infrastructures? The fundamental scientific issue of these challenges is the weakening mechanism of inhomogeneous slopes at different scales as it determines the slope responses under various geological and environmental conditions.The proposed research aims to explore the fundamental mechanism of progressive slope failure and its impacts on infrastructures via a multiscale and probabilistic modelling approach. It enables the large deformation of slopes to be conveniently analysed by FEM as boundary value problem (BVP), while the local fracturing, cracking, or discontinuous behaviours of soil to be evaluated in smaller discrete subdomains through granular mechanics by DEM. The boundary condition of DEM assembly is derived from the global deformation of FEM meshes. In the analysis, the soil/rock properties (e.g. elastic modulus, friction coefficient, strength, and fluid permeability) will be evaluated as random fields with spatial variabilities. The numerical modelling can effectively bridge the gap between the microscopic material properties and the overall macroscopic slope responses. In the numerical modelling, the contributions of material inhomogeneity and discontinuity to slope failure and subsequence landslide spreading can be effectively investigated. The internal fracture would occur naturally when the loading stress exceeds the particle bonding strength at the microscale, which avoids the use of some phenomenological constitutive laws in conventional continuum modelling. As a multidisciplinary research, this project will involve the subjects of geotechnical engineering, computational geotechnics, geology, statistics, soil/rock mechanics and granular mechanics. The proposed numerical model will benefit all researchers and stakeholders in land planning and management by providing efficient and reliable numerical modelling approaches. This will support the landslide risk evaluation, hazard mitigation and long-term land management, from which the environmental, social, and economic benefits can be achieved. As a result, the decision makers would have greater confidence in slope failure risk assessments on which they are basing their infrastructure investment considerations. Consequently, hazard warning systems, protections and land utilization regulations can be implemented, so that the loss of lives and properties can be minimized without investing in long-term, costly projects of ground stabilization.

在英国和全球范围内，各种规模的边坡失稳对韧性城市的可持续发展至关重要，因为它的发生会严重威胁人口、基础设施、公共服务和环境。例如，英国地质调查局估计，英国 10% 的斜坡被列为中度至严重滑坡风险，超过 7% 的主要交通网络位于这些地区。这些斜坡可能会在长时间的潮湿天气或更强烈的短时降雨事件中发生故障。目前，公众对边坡失稳风险的认识较高，但对其基本失稳机理和对策的认识还很有限。这主要是由于分析多尺度响应和表征斜坡材料特性的空间不均匀性存在困难。具有成熟经验模型的实验室和数值研究可以解释一些特定边坡破坏事件的一般特征，但不能普遍应用。需要解决一些具有挑战性的问题，例如i）如何开发具有多尺度建模能力的可靠数学模型来分析斜坡的渐进破坏？ ii) 如何解决实际坡度的空间变异性和不确定性，例如材料特性、断裂、流体渗透性？ iii) 如何准确估计滑坡的蔓延范围及其对基础设施的影响？这些挑战的根本科学问题是不同尺度下不均匀边坡的弱化机制，因为它决定了不同地质和环境条件下边坡的响应。本研究旨在通过多尺度和概率建模方法探索渐进式边坡破坏的基本机制及其对基础设施的影响。它使得边坡的大变形可以通过 FEM 方便地作为边值问题 (BVP) 进行分析，而土体的局部破裂、开裂或不连续行为可以通过 DEM 的颗粒力学在较小的离散子域中进行评估。 DEM 装配的边界条件源自 FEM 网格的全局变形。在分析中，土壤/岩石特性（例如弹性模量、摩擦系数、强度和流体渗透性）将被评估为具有空间变异性的随机场。数值建模可以有效地弥合微观材料特性和整体宏观斜率响应之间的差距。在数值模拟中，可以有效地研究材料不均匀性和不连续性对边坡破坏和后续滑坡扩展的贡献。当加载应力超过微观尺度上颗粒的结合强度时，内部断裂就会自然发生，这就避免了使用传统连续介质建模中的一些唯象本构定律。作为一项多学科研究，该项目将涉及岩土工程、计算岩土学、地质学、统计学、土/岩石力学和颗粒力学等学科。所提出的数值模型将通过提供高效可靠的数值建模方法，使土地规划和管理中的所有研究人员和利益相关者受益。这将支持滑坡风险评估、减灾和长期土地管理，从而实现环境、社会和经济效益。因此，决策者对基础设施投资考虑的边坡失稳风险评估会更有信心。因此，可以实施危险预警系统、保护和土地利用法规，从而最大限度地减少生命和财产损失，而无需投资长期、昂贵的地面稳定项目。