【作者】 杨宁；

【导师】 齐梅兰；

【作者基本信息】 北京交通大学 ， 防灾减灾工程及防护工程， 2014， 硕士

【摘要】 洪水期间,河流水位超过滩地高程,水流在主槽和滩地内流动,形成漫滩水流。桥台置于漫滩上将会阻碍水流流动,特别是在河流汛期时,漫滩水流将会对桥台基础形成不可忽视的局部冲刷作用,影响桥梁运营安全。因此,研究漫滩河流桥台周围水流结构及冲刷深度,对桥梁的灾害防御具有重要意义。论文针对漫滩河流桥台周围水流作用下的冲刷问题,通过理论分析和水槽试验,探讨了漫滩河流桥台周围的水流结构特征和冲刷深度变化规律。对影响漫滩河流桥台冲刷深度的主要因素进行了分析,确定了主要因素与漫滩河流桥台冲刷深度的关系。基于试验数据,通过量纲分析与多元回归分析方法建立了漫滩河流桥台最大冲刷深度计算公式。进一步采用前人数据对公式进行了验证,结果表明,本文公式大部分计算值在Sturm公式值与Melville公式值之间,同时与Dongol公式值较为接近,表明本文给出的漫滩河流桥台冲刷计算公式具有较好的可信度。更多还原

【Abstract】 ABSTRACT:During the flood period, the floodplain is submerged by the water flows, resulting in the formation of overbank flow, which is different from the flow in the main channel. The overbank flow disturbed by bridge abutments located in the floodplain would cause local scour around the structures, causing high risk to bridge operation. So it’s of great importance to study the flow characteristics and scour depth around the abutments under overbank flow.This dissertation mainly focuses on local scour in vicinity of bridge abutment under floodplain river conditions and discusses the flow structure and floodplain scour depth around bridge abutments through theoretical analysis and flume tests. The main factors affecting the floodplain abutment scour depth were analyzed and the relationship between main factors and floodplain abutment scour depth was determined. The formula of maximum scour depth around the abutment in the floodplain was established by dimensional analysis and multiple regression method. Compared with the conventional formulae, most of the calculated values of the new formula are between Sturm’s and Melville’s values, and relatively close to the Dongol’s value, showing good credibility of the formula presented in this dissertation.更多还原