Deep sea environment construction of bridge pier affects the area of water movement in the original,bridge pier local scour damage.For research and to solve this problem,this article with haiyan bridge 3# and 5# pier as the research object,based on the analysis of the basic geology and hydrology,on the basis of engineering geological conditions,combined with field monitoring scheme,analyzes the construction of bridge pier local scour mechanism and practical in the process of scour depth,and comparison of several common local scour theory formula,puts forward corresponding protective technology.Study found that:under the condition of deep sea bridge pier mainly by two hydraulic upstream runoff and tide effect,and wake vortex in on both sides of the piers and the scour pit;Monitoring results show that the flow law of disorder during bridge construction,the construction of the hydraulic late to bed scour rate basically stable at 4 mm/day,eight months in the monitoring period,4,5# bridge scour depth were 1.23 and 1.32 m on average,amounted to only 8% to 10% of the theory of scour depth,the river bed in bridge operation also by local scour;In addition,this paper puts forward the environment combined with the active protection for the deep and flow kinetic energy reduction protection technology solutions,so as to bridge pier scour prevention technique of deep-sea environment provides certain reference and data to support.%深海环境修建桥梁墩柱会影响该区域原有的海水运动特征,造成桥梁墩柱局部冲刷破坏.为研究和解决这一问题,以海燕大桥3#和7#桥墩为研究对象,在分析其基本地质和水文工程地质条件的基础上,结合现场监测方案,分析了桥梁墩台施工过程中的局部冲刷机理和冲刷深度,并且对照几种普遍的局部冲刷理论公式,提出了对应的防护技术手段.研究发现:深海条件下桥墩主要受上游径流和潮汐两种水力作用影响,并在桥墩两侧产生尾流旋涡和冲刷坑;监测结果表明在桥墩施工期间水流规律紊乱,施工后期水力对河床冲刷速率基本稳定在4 mm/d,在监测周期8个月内,3#、7#桥梁平均冲刷深度分别为2.23,1.82 m,仅达到理论冲刷深度的8%~10%,说明在桥梁运营中河床还会受到局部冲刷作用;此外,本文提出了针对深水环境下结合主动防护和水流动能减速两类防护技术方案,以期为深海环境下桥梁墩柱的防冲刷技术提供一定参考和数据支撑.
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