嘉陵江特大桥水中承台围堰施工关键技术

以G5京昆高速广元至绵阳段扩容工程LJ3合同段嘉陵江特大桥施工为背景,结合现场施工方案、施工技术,对水中承台围堰施工技术进行分析。嘉陵江特大桥主桥采用95 m+180 m+95 m连续刚构,引桥采用25、50、48.5 m简支T梁,该文以主桥2^(#)、3^(#)墩承台为例,水中围堰采用锁扣钢管桩形式。围堰方式遵循地理环境和水文条件、工程的用途和功能、工程的经济性和可行性等原则。施工过程中合理规划施工工序,同时进行桩基栈桥的施工和围堰引孔作业。最后重点加强对锁口的检查,做好围堰关键位置的变形监测,以保证安全施工。

Taking the construction of the extra-large bridge over Jialing River in LJ3 contract section of G5 Beijing-Kunming Expressway from Guangyuan to Mianyang as the exemplar,based on the on-site construction scheme and technology,the construction technology of underwater pile cap cofferdam is analyzed.The main body of Jialing River Bridge is made of a continuous steel structure of 95 m+180 m+95 m,and the approach bridge adopts 25 m,50 m and 48.5 m simply supported T-girder.In this paper,the 2~3^(#)caps of the main bridge are taken as exemplars,and the underwater cofferdam is in the form of locked steel pipe pile.The cofferdam mode follows the principles of geographical environment and hydrological conditions,the use and function of the project,and the economy and feasibility of the project.In the process of construction,the construction procedure is planned reasonably,and the construction of pile foundation trestle and cofferdam are carried out at the same time.Finally,we focus on strengthening the inspection of the lock,ensure the deformation monitoring of the key position of the cofferdam to guarantee safe construction.