钱塘江河口两座跨海大桥潮动力叠加影响的数值研究

发布时间：2018-05-15 23:04

本文选题：钱塘江河口 + 跨海大桥　；参考：《浙江大学》2017年硕士论文

【摘要】：钱塘江河口处于上海大都市圈的核心位置,周围各城市间经济贸易往来密切。杭州湾作为钱塘江河口的口外海滨段,水域面积辽阔,在为水运交通提供了便利的同时,却对陆路交通造成了天然阻碍。为了解决这一难题,跨海桥梁的建设是个行之有效的方法。在钱塘江河口区域已建及规划在建的长度超过10km的跨海桥梁总数已超过6座。河口中大规模的桥梁工程建设势必会对各潮动力要素造成影响,而潮位、潮流等潮动力要素又关系着沿岸水利工程设施的建造标准。目前,国内外的研究多集中在分析单座跨海大桥的影响上而较少关注两座及以上跨海大桥共同建设的情况。因此,为了探究同一河口区域多座桥梁的潮动力叠加影响问题,本文采用数值模拟的方法进行了初步研究。首先,建立包含钱塘江河口与长江口的大范围数值模型,与实测资料对比验证后,分析了杭州湾区域的潮动力特征,并采用计算得到的水位结果,为钱塘江河口的小尺度精细模型提供外海开边界条件。然后,保留主桥桥墩原型,仅对跨海大桥中尺寸较小又数量众多的引桥桥墩概化并加入小范围的钱塘江河口模型当中。最后,分别探究了两座桥梁的独立和叠加影响,讨论分析钱塘江河口潮位、潮流以及纳潮量的响应。主要结果如下:(1)杭州湾内水流呈现明显的往复流特性,涨潮历时小于落潮历时,涨潮流速大于落潮流速。此外,进出杭州湾的潮流由于受到湾口舟山群岛的阻隔,主要分为五股。其中潮流通量最大的为镇海-定海通道,最小的为衢山-洋山通道。(2)桥梁的建设对潮动力的影响,总体上体现在对潮汐能量的削弱上,包括潮流流速的降低,潮差的减小及纳潮量的缩减。其中,潮差与纳潮量的响应结果可以相互印证。此外,由于杭州湾独特的喇叭形岸线特征,潮差受桥梁建设影响的值向上游不断增大,直至距闻堰60km处,以两桥共同建设工况为例,最多减小4.6cm。(3)两座跨海大桥叠加影响情况下,在对潮动力要素的沿程及全局的总体影响方面,杭州湾大桥的作用占据主导地位,嘉绍大桥仅在其桥位附近有较为突出的影响。例如潮位和纳潮量的沿程变化结果中,可以发现总体趋势仍是由杭州湾大桥所产生的影响所决定,但嘉绍大桥会对其桥位附近水域产生较剧烈影响。
[Abstract]:Qiantang River estuary is located at the core of Shanghai Metropolitan area. Hangzhou Bay, as the seaside section of Qiantang River estuary, has a vast water area, which provides convenience for water transportation, but also creates natural obstacles to land transportation. In order to solve this problem, the construction of bridge across the sea is an effective method. In the Qiantang River Estuary area, the total number of cross-sea bridges that have been built and planned to exceed 10km is more than 6. The large-scale bridge construction in the estuary is bound to affect the tidal dynamic elements, and tidal level, tidal current and other tidal dynamic elements are related to the construction standards of coastal water conservancy facilities. At present, the domestic and foreign studies mainly focus on the analysis of the impact of single sea crossing bridge, and pay less attention to the joint construction of two or more cross-sea bridges. Therefore, in order to investigate the effect of tidal dynamic superposition on several bridges in the same estuary region, the numerical simulation method is used to study the effect of the tidal superposition. Firstly, a large-scale numerical model including the Qiantang River Estuary and the Yangtze Estuary is established. After comparing with the measured data, the tidal dynamic characteristics in the Hangzhou Bay region are analyzed, and the calculated water level results are used. It provides the open boundary conditions for the small scale fine model of Qiantang River estuary. Then, the prototype of the main bridge pier is retained, and only the small and large number of bridge piers in the cross-sea bridge are generalized and added to the small Qiantang River estuary model. Finally, the independent and superimposed effects of the two bridges are investigated, and the responses of tidal level, tidal current and tidal absorption volume in Qiantang River estuary are discussed. The main results are as follows: (1) the characteristics of reciprocating current in Hangzhou Bay are obvious. The duration of high tide is less than that of falling tide, and the velocity of rising tide is greater than that of falling tide. In addition, the tidal current in and out of Hangzhou Bay is mainly divided into five streams because it is blocked by the Zhoushan Islands at the mouth of the Bay. Among them, the largest tidal flux is the Zhenhai-Dinghai channel, and the smallest is the Qu-Shan-Yangshan Passage. 2) the influence of the construction of the bridge on the tidal power is reflected in the weakening of the tidal energy, including the reduction of the tidal current velocity. The decrease of tidal range and the reduction of tidal absorption. Among them, the response results of tidal range and tidal absorption can be verified mutually. In addition, due to the unique characteristics of the loudspeaker shoreline in Hangzhou Bay, the value of tidal range affected by bridge construction is increasing upstream, up to the point of 60km from Wenyan, taking the joint construction condition of the two bridges as an example, the maximum reduction is 4.6 cm. 3) under the influence of the superposition of the two sea crossing bridges, The effect of Hangzhou Bay Bridge plays a dominant role in the overall influence on the course and overall situation of tidal dynamic elements, and the Jia-Shao Bridge has a more prominent influence only near its bridge location. For example, the results of tidal level and tidal absorption along the course show that the overall trend is still determined by the influence of Hangzhou Bay Bridge, but the Jiazhao Bridge will have a severe effect on the water near the bridge.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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