长江上游典型浅滩束水丁坝影响幅度研究

发布时间：2018-03-23 15:30

本文选题：航道整治　切入点：丁坝　出处：《重庆交通大学》2017年硕士论文

【摘要】：航道整治是提高内河航道等级、改善通航条件投资省、见效快的主要方法,束水丁坝是浅滩整治中最常见的整治建筑物。目前,对丁坝断面上游河段的水位雍高区域及下游回水区域影响幅度研究较多,主要集中在平面区域,而对丁坝影响的水位、流量等垂向幅度还没有得到很好研究。因此,开展束水丁坝在垂向上的影响幅度研究意义重大。本文采用二维水流数学模型、概化水槽试验,开展不同类型实际典型浅滩整治中丁坝的影响幅度进行研究。通过对丁坝周围水流特性进行分析和试验,研究了丁坝几何尺寸对流量影响幅度的变化规律,得到如下主要成果与结论:(1)对于水槽束水丁坝:丁坝对流速变化率α影响的极大值流量会随着丁坝尺寸的变化而改变,不一定出现在丁坝刚好淹没所对应的流量,即整治流量,有可能会出现在更大的流量级。流速变化率α最大值主要出现在坝上水深超高0-2cm,流量Q=(50,100)L/s区间范围内。(2)随着水槽流量增大,收缩断面下移,流速变化率α减小,最大影响区域约在丁坝下游0-100cm之间。流速变化率α最大值出现对应的流量与坝长无明显相关性,而α最大值出现对应的流量和坝高h呈正相关;坝高h一定时,最大影响流量基本固定。定义了最大影响线,流量越大,最大影响线会向下游移动;丁坝的几何尺寸对最大影响线无明显影响。通过对半衰减流量Qbm与坝高h和坝长b的单因素分析的结果进行拟合,建立了矩形水槽束水丁坝半衰减流量Qbm与丁坝几何尺寸的经验关系式,验证吻合较好。(3)对三类典型实际浅滩控制单因素坝顶高程和坝长对来流量Q的影响幅度进行研究,控制单因素坝顶高程h和坝长b对来流量Q的影响幅度分析,确定了相应浅滩束水丁坝最大影响流量和最大影响超高范围。得出流速变化率α与来流量的关系、流速变化率最大值αmax与丁坝高程和长度的关系、相应束水丁坝影响流量幅度与丁坝几何尺寸及来流条件的经验关系式,验证效果基本令人满意。(4)分别对顺直、弯曲和汊道浅滩拟定的工况进行数模流场计算,综合上滩指标显示船舶能够自航上滩,并依据已得经验公式算出影响流量幅度,结合实际滩险成因分析,推荐了丁坝几何尺寸。
[Abstract]:Waterway regulation is the main method to improve the grade of inland waterway, improve navigation conditions, and achieve fast results. Shuishui-dike is the most common regulation building in shoal regulation. At present, There is much research on the influence range of the upstream reach of the spur dike section on the uvula and downstream backwater area, mainly in the plane area, but the vertical amplitude of the water level and discharge of the spur dike section has not been well studied. It is of great significance to study the influence range of beam groin dam in vertical direction. In this paper, a two-dimensional flow mathematical model is used to generalize the flume test. The influence range of spur dike in different types of typical shoal regulation is studied. By analyzing and testing the characteristics of the flow around the spur dike, the variation law of the influence of the geometry size of the spur dike on the discharge amplitude is studied. The main results and conclusions are as follows: (1) the maximum flow rate of the effect of the spur dike on the velocity change rate 伪 will change with the change of the size of the spur dike, not necessarily in the discharge corresponding to the inundation of the spur dike, that is, the regulation flow rate. It is possible to appear in a larger flow level. The maximum velocity change rate 伪 is mainly found in the water depth of the dam between 0 and 2 cm, and the flow rate is within the range of Q=(50100)L/s. 2) with the increase of the flume flow rate, the shrinkage section moves down, and the velocity change rate 伪 decreases. The maximum influence area is about between the downstream 0-100cm of the spur dike. There is no obvious correlation between the maximum velocity change rate 伪 and the dam length, but there is a positive correlation between the corresponding flow rate and the dam height h, and when the dam height h is fixed, the maximum value of 伪 is positively correlated with the dam height h. The maximum influence flow is fixed basically. The maximum influence line is defined. The larger the flow rate, the more the maximum influence line will move downstream. The geometric size of spur dike has no obvious effect on the maximum influence line. The results of one-factor analysis of dam height h and dam length b are fitted with the half-attenuated flow Qbm. The empirical relationship between half-attenuation flow Qbm and geometry size of spur dike in rectangular flume is established. It is verified that it is in good agreement. The influence of single factor height and dam length on the flow Q of three typical types of actual shoal control is studied. Based on the analysis of the influence of single factor height h and dam length b on the incoming discharge Q, the maximum influence discharge and the maximum influence super high range of the corresponding shoal beam spur dam are determined. The relationship between the velocity change rate 伪 and the incoming flow rate is obtained. The relationship between the maximum velocity change rate 伪 max and the height and length of the spur dike, the empirical relationship between the influence amplitude of the corresponding beam spur dike and the geometry size and the flow condition of the spur dike, the verification effect is basically satisfactory. The mathematical model flow field calculation is carried out under the working conditions proposed by the bend and the inlet shoal. The synthetic beach index shows that the ship can sail on the beach by itself, and according to the empirical formula, the influence flow range is calculated, and combined with the analysis of the causes of the actual shoal risk, the geometric size of the spur dike is recommended.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U617.91

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