Scour at culvert outlets under ice cover and ice jam conditions

在公路系统的设计和施工中，主要考虑的问题之一是通过涵洞系统输送支流排水。涵洞出水口急水流冲刷的研究已经进行了几十年。各种研究已经检查了许多影响侵蚀程度的冲刷参数；然而，对寒区涵洞出口设计及冲蚀控制的研究较少。在寒冷的冬季，涵洞可能完全被入口覆盖，在早春也可能面临冰堵塞，这可能导致路堤洪水和过度冲刷。此外，由于冰覆盖和冰塞的附加边界，涵洞内的流场与明渠条件下的流场不同。涵洞出水口因冰雪覆盖和冰堵造成的过度冲刷会导致路堤淹水，进而导致公路破坏。覆盖和堵塞涵洞入口的影响从未在实验中得到解决。此外，还没有可用的实验或数值模拟来研究覆盖条件下涵洞内的流动曲线。本文主要对覆盖和冰塞条件下涵洞冲刷进行了试验和数值研究。评估的目标如下：a)评估在冰雪覆盖条件下涵洞出口的冲刷发展情况；B)建立描述冲刷过程与水流强度、涵洞形状、颗粒粒度和边界条件之间关系的相关方程；C)确定冰盖和冰塞如何改变非均匀沙地涵洞出口冲刷孔的几何形状；D)研究冰堵塞对涵洞出水口冲刷的影响；E)建立模拟矩形涵洞出口冲刷过程的数值模型。在本研究中，将在三个不同的水力水槽进行小、中、大型实验。实验与数值模拟相结合，将产生一组经验方程，用于预测冰条件下涵洞出口的最大冲刷深度。对水利工程中涵洞的设计与养护进行综述。我们将深入讨论冰盖和冰塞的影响。本研究将为解决涵洞出水口的冲刷问题提供一种实用的方法。预测涵洞出水口冲刷的大小和几何形状的能力是加拿大高速公路侵蚀控制和管理中非常有用的评估工具。该研究将有利于实践工程师和科学界。

One of the major considerations in the design and construction of a highway system is the conveyance of tributary drainage through a culvert system. The investigation of scour by swift-flowing water at culvert outlets has been on-going for several decades. Various studies have examined many scour parameters that affect the degree of erosion; however, there is limited research on culvert outlet design and scour control in cold regions. Culverts may become fully inlet-covered in rigid winter climates and may also face ice jamming in early spring, which can result in embankment flooding and excessive scour. Additionally, due to the extra boundary imposed by ice cover and ice jam, the flow field inside the culvert is different from that under open channel conditions. Excessive scour at culvert outlets due to ice cover and ice jamming cancause embankment flooding, which can result in highway failure. Theimpact of covered and jammed culvert inlets has never been addressedexperimentally. Furthermore, there are no available experimental ornumerical simulations to investigate the flow profiles inside theculvert under covered conditions. The research focuses on the experimental and numerical investigation of culvert scour under ice cover and ice jam conditions. The following objectives will be evaluated: a) to assess temporal scour development at culvert outlets under ice cover conditions; b) to establish associated equations describing the dependence of scour processes on flow intensity, culvert shape, particle grain size, and boundary conditions; c) to determine how ice cover and ice jams alter the geometry of scour holes at culvert outlets in non-uniform sands ; d) to investigate the impacts of ice jamming on the scouring at culvert outlets; e) to develop a numerical model for simulating the scour process for rectangular culvert outlets. In the proposed research, small scale, medium scale and large scale experiments will be conducted at three different hydraulic flumes. The experiments, together with numerical simulation, will generate a set of empirical equations that will predict the maximum scour depth at culvert outlets under ice conditions. A compilation of review on culvert design and maintenance in hydraulic engineering will occur. The ice cover and ice jam impacts will be discussed in depth. The present research will provide a practical approach to address the scouring at culvert outlets. The ability to predict the magnitude and geometry of scour at culvert outlets is an extremely useful evaluation tool in the control and management of erosion along highways in Canada. The research will be beneficial to practicing engineers and the scientific community.