Effects of debris damming on bridges**

当前研究计划的主要目标是研究碎片运动和对桥梁的影响的机制，并为开发新的可靠的设计工具做出贡献。本文提出的研究思路是实地调查的观察和发现的直接结果，也是对当前设计指南和标准中关于碎片运动和影响的规定的批评和缺乏明确性/有效性的直接结果。****提出的项目是一个新颖的发展，其重点是数值模拟和分析极端水动力条件下碎片坝和相关荷载对桥墩的影响。虽然以往的研究都是实验性的，但本研究将通过在各种洪水条件和不同湍流水动力条件下进行详细的数值分析和调查，为这方面的知识做出贡献。本研究的目的是建立一个模拟移动床存在的数值模型，以准确模拟碎片筑坝对桥墩的冲刷。该模型将使用现有的实验数据进行校准和验证。随后，将对不同水流条件和桥墩构型下的桥墩冲刷进行模拟。研究的最终结果将为申请人的工业合作伙伴（Golder）提供一个更准确的预测数值工具，以协助他们进行省和国家的洪水灾害研究。与碎屑运动及其相关影响相关的主要挑战之一是在这些瞬态高速流动条件下碎屑运动的随机性。目前使用的确定性方法无法充分捕捉到与碎片移动有关的物理过程，因此，本文提出的研究计划旨在通过执行高质量、高分辨率、随比例变化的碎片运动和加载数值模型来解决这一问题，以帮助开发一个概率框架，以便在洪水设计指南和标准中实施危害和风险评估。**

The main goals of the current research program are to investigate the mechanisms of debris motion and impacts on bridges and to contribute to the development of new and reliable design tools. Research ideas proposed herein are direct results of observations and findings stemming from field investigations as well as of the criticism and the lack of clarity/validation of the provisions of the current design guidelines and standards with respect to debris motion and impact. ****The proposed project is a novel development which focuses on the numerical simulation and analysis of the influence of debris damming and associated loads on bridge piers in extreme hydrodynamic conditions. While of the previous studies were experimental, the proposed study will contribute to the knowledge through conducting a detailed numerical analysis and investigation under various flood conditions and under different turbulent hydrodynamic conditions. The objective of the current study is to build a numerical model simulating the presence of a mobile bed that can accurately simulate the scour at the bridge piers caused by debris damming. The model will be calibrated and validated using available experimental data. Subsequently, a number of scenarios will be simulated to characterize scour at bridge piers under different flows conditions and pier configurations. The final product of the study will provide the applicant's industrial partner (Golder) with a more accurate predictive numerical tool to assist with their provincial and national flood hazard studies. One of the primary challenges related to debris motion and associated effects is the stochastic nature of debris motion within these transient, high-velocity flow conditions. The currently used deterministic approach cannot adequately capture the physical processes involved in debris transport and, as such, the proposed research program presented herein aims to address this issue by performing high-quality, high-resolution, scale-varying numerical modelling of debris motion and loading to aid in the development of a probabilistic framework for the implementation in hazard and risk assessment across flood design guidelines and standards.**