Effects of debris damming on bridges**

当前研究计划的主要目标是调查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。这里提出的研究想法是实地调查的观察和结论的直接结果，也是对现行设计准则和标准中关于碎片运动和撞击的规定的批评和缺乏清晰度/验证的直接结果。*该项目是一项新的发展，重点是对极端水动力条件下泥石坝及其相关荷载对桥墩的影响进行数值模拟和分析。虽然以前的研究大多是试验性的，但拟议的研究将通过在不同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来帮助了解这些知识。目前研究的目的是建立一个数值模型，模拟移动床的存在，能够准确地模拟泥石坝对桥墩的冲刷。该模型将使用现有的实验数据进行校准和验证。随后，将模拟多个场景，以描述不同水流条件和桥墩配置下桥墩的冲刷特性。这项研究的最终成果将为申请者的工业伙伴(戈尔德)提供更准确的预测数值工具，以帮助他们进行省级和全国性的洪水风险研究。与泥石流运动及其相关效应有关的主要挑战之一是，在这些瞬变、高速流动条件下，泥石流运动的随机性。目前使用的确定性方法不能充分捕捉碎片运输所涉及的物理过程，因此，本文提出的拟议研究计划旨在通过对碎片运动和加载进行高质量、高分辨率、变尺度的数值模拟来解决这一问题，以帮助开发概率框架，以便在洪水设计指南和标准中实施危险和风险评估。

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.**