河口地区潮流作用下桥墩局部冲刷深度研究

发布时间：2018-03-29 02:15

本文选题：潮流　切入点：局部冲刷　出处：《重庆交通大学》2014年硕士论文

【摘要】：桥梁在我国交通运输中扮演着极其重要的角色，桥梁的安全运行是我国经济发展的基本保障。据统计，水毁是导致桥梁破坏的一个重要原因，而桥墩的局部冲刷又是导致桥梁水毁的主要因素之一，所以能够准确地预知桥墩局部冲刷的深度，合理布置桥墩埋深，是桥梁安全运行的根本保障。先前，，此方面专家学者已对建在河流上桥梁的桥墩局部冲刷深度做了大量和深入的科学研究，并且创建了多个可供桥梁设计参考的桥墩局部冲刷深度的计算公式。然而，随着我国桥梁建造技术的不断创新与发展，以及沿海地区尤其河口海湾地区经济的飞速发展，大型、特大型跨海大桥正如雨后春笋般涌现在我国沿海地区。这些桥梁中多数桥墩处于水流条件极为复杂的潮流中，并且应运而生了花样翻新、种类繁多的各式桥墩结构，原有预测公式已难以适用当前形势。为了保障建在海区中的桥梁安全，桥梁领域中急需对处在河口海域中受到潮流作用的桥墩局部冲刷深度进行全面且深入的探究。如今，不论桥梁设计还是科学研究，关于桥墩局部冲刷深度的计算绝大多数是依据桥墩的特征条件、桥墩附近的流场条件和泥沙条件，按规范公式计算得到相应结果。然而，因为桥墩附近水流环境十分复杂，桥墩局部冲刷机理和相关理论仍旧未被充分认知。论文意在归纳先前国内外专家学者研究成果的基础上，对影响桥墩局部冲刷深度的各因素进行总结，采用无量纲法及多元线性回归分析，结合大量实测数据，从而推导出相应条件下的桥墩局部冲刷深度的计算公式。根据77省道延伸段所在的瓯江河口地区潮流动力的变化特点，采用有限元数学模型软件对该处海域进行模拟。论文着重对77省道延伸线洞头峡大桥、深门大桥和浅门大桥三座桥梁桥位处的水流条件进行了数模计算，为了提高数学模型对工程所在海区水动力特征数学模拟的精确度，论文在数学模型计算时采用了大小嵌套的计算方法。并将验证后的桥墩局部冲刷公式分别与当今常用的几个局部冲刷公式共同用于工程计算，并进行相关的比较分析。通过与设计研究中常用的几个桥墩局部冲刷常用公式比较发现，本文提出的桥墩局部冲刷公式结构简单，计算结果精度较高，可为相关区域中桥梁工程的桥墩局部冲刷深度的估算提供参考依据。
[Abstract]:Bridges play an extremely important role in the transportation of our country. The safe operation of bridges is the basic guarantee for the economic development of our country. According to statistics, water destruction is an important reason leading to the destruction of bridges. The local scour of bridge pier is one of the main factors leading to bridge water destruction, so it is the fundamental guarantee of bridge safe operation to accurately predict the depth of local scour of bridge pier and arrange the buried depth of pier reasonably. In this field, experts and scholars have done a lot of scientific research on the local scour depth of bridge piers built on rivers, and have created many formulas for calculating the local scour depth of bridge piers which can be used as reference for bridge design. With the continuous innovation and development of bridge construction technology in China, and the rapid development of economy in coastal areas, especially in estuarine and gulf areas, The super-large cross-sea bridges sprang up in the coastal areas of our country. Most of the piers of these bridges are in the tidal current of extremely complex flow conditions, and have emerged as the times require, and various types of pier structures have emerged. In order to ensure the safety of bridges built in the sea area, the local scour depth of the pier in the estuarine sea area is urgently needed to be comprehensively and deeply explored. Nowadays, regardless of bridge design or scientific research, the calculation of local scour depth of bridge piers is mostly based on the characteristic conditions of the piers, the flow field conditions and sediment conditions near the piers, and the corresponding results are obtained according to the standard formula. Because the water environment near the pier is very complex, the local scour mechanism and related theories of bridge pier are still not fully recognized. The purpose of this paper is to sum up the previous research results of experts and scholars at home and abroad. The factors affecting the local scour depth of bridge piers are summarized. The formula for calculating the local scour depth of piers under the corresponding conditions is deduced by using dimensionless method and multivariate linear regression analysis combined with a large number of measured data. According to the variation characteristics of tidal current dynamics in Oujiang Estuary area, where the extension section of the 77 provincial highway is located, the finite element mathematical model software is used to simulate the sea area there. The paper focuses on the Dongtou Gorge Bridge, the 77 provincial extension line. In order to improve the accuracy of the mathematical simulation of hydrodynamic characteristics in the sea area where the engineering is located, the flow conditions at the three bridges of the Shenmen Bridge and the shallow Gate Bridge are numerically simulated. In this paper, the calculation method of size nesting is used in the calculation of mathematical model, and the verified local scour formula of bridge pier is used in engineering calculation together with several commonly used local scour formulas, and the relative comparative analysis is carried out. By comparing with some commonly used formulas for local scour of bridge piers in design and research, it is found that the local scour formula proposed in this paper is simple in structure and high in accuracy. It can be used as a reference for estimating the local scour depth of bridge piers in relevant regions.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U443.22;U442.32

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