峡道海域流速分布研究

发布时间：2018-05-06 01:20

本文选题：流速分布 + 峡道　；参考：《浙江大学》2017年硕士论文

【摘要】：秀山大桥横跨舟山市官山岛与秀山岛之间水深流急的峡道海域。海床岩面倾斜度大导致海底流速很大,给桥梁基础施工带来极大困难。研究峡道效应及流速分布,对桥梁施工具有重要意义。本文基于水槽试验和数值模拟手段首次对秀山大桥海域流速分布进行深入研究。首先,在水槽中对凸底条件下垂向流速分布作了试验研究。试验在浙江大学近海馆精密水槽中进行,槽底铺设三角形和梯形各3种玻璃凸底床加1种平底,按3种流量进行试验共获得21组数据。据此建立了抛物线型流速垂向分布公式,分析表明待定系数与凸底迎水坡度J呈显著的线性关系,且a和c随J增大而减小,b则反之;无量纲最大流速位置随J增加而下移,最低在相对水深0.41处,偏离水面较远;而最大流速与断面平均流速之比接近为常数。本文公式计算的流速分布与水槽试验资料一致,说明公式客观地反映了凸底明渠的流速分布规律。然后,采用Delft3D软件数值模拟了秀山大桥海域流场,现场测量获取两个测站的潮位和流速数据对模型进行验证,结果良好。选取了秀山大桥南侧5个桥墩各6条观测垂线,模拟得到了这30条垂线的流速分布数据。分析建立了潮段平均无量纲流速垂向分布公式。结果表明,潮段平均无量纲流速在7#～10#桥墩处自海面向海底减小,而11#桥墩处自海面向海底增加,最大值出现在海底,主要与海底凸起岩面有关。11#桥墩处的最大流速涨潮显著大于落潮,7#桥墩处的最大流速落潮显著大于涨潮,主要与柯氏力作用有关。
[Abstract]:Xiushan Bridge spans the waters between Guanshan Island and Xiushan Island. The large slope of seabed rock leads to high velocity of sea floor, which brings great difficulties to the construction of bridge foundation. It is of great significance to study the isthmus effect and velocity distribution for bridge construction. In this paper, the velocity distribution of Xiushan Bridge is studied for the first time based on flume test and numerical simulation. First, the vertical velocity distribution under convex bottom is studied experimentally in the flume. The experiment was carried out in the precision flume of Zhejiang University Offshore Pavilion. The triangular and trapezoidal bed with three kinds of glass-convex bottom and one flat bottom were laid on the bottom of the tank. 21 groups of data were obtained according to the three kinds of flow rate. The vertical distribution formula of parabolic velocity is established. The analysis shows that the undetermined coefficient has a significant linear relationship with the gradient J of the convex bottom, and that a and c decrease with the increase of J, whereas the position of the dimensionless maximum velocity moves down with the increase of J. The lowest is at the relative depth of 0.41, which is far away from the water surface, and the ratio of the maximum velocity to the average velocity of the section is close to constant. The velocity distribution calculated by the formula is consistent with the experimental data of the flume, which shows that the formula objectively reflects the velocity distribution law of the open channel with convex bottom. Then, the flow field of Xiushan Bridge is simulated numerically by Delft3D software, and the data of tidal level and velocity of two stations are obtained in the field to verify the model, and the results are satisfactory. Five piers on the south side of Xiushan Bridge were selected and 6 vertical lines were observed, and the velocity distribution data of the 30 vertical lines were obtained by simulation. The vertical distribution formula of average dimensionless velocity in tidal section is established. The results show that the average dimensionless velocity of tidal section decreases from the sea level to the sea floor at the pier of the 7 #Li 10# bridge, but increases from the sea level to the sea floor at the 1 1# pier, and the maximum velocity appears at the bottom of the sea. The maximum velocity tide at the pier of the bridge is significantly larger than that at the pier at the fall tide, which is mainly related to the action of Coriolis force.
【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】：U442.31

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