合福客专铜陵长江大桥主桥5号墩承台施工技术

Construction Technology for Pile Cap of Pier 5 of Tongling Yangtze River Bridge of Hefei-Fuzhou Passenger Dedicated Line

研究目的:铜陵长江大桥主桥5号墩位于长江大堤坡脚处,承台施工时的基坑大开挖无疑会对长江大堤造成巨大的破坏,必须采取可靠的基坑支护方式,尽快完成承台施工及基坑的回填,确保承台施工后能够完全恢复大堤的原有防洪功能。研究结论:承台基坑支护方案经过多种方案的对比分析后,采用了支护结构易于施工及基坑内便于机械开挖取土的单层内支撑钢板桩围堰支护方式,施工简便快捷,又可确保长江大堤在施工期间的安全及施工后的可恢复性;承台混凝土一次性整体浇筑,根据承台大体积混凝土施工期的水化热温度场仿真分析的结果,采用了埋设冷却水管路降温系统和电子测温元件的温度监测系统,有效保证了承台混凝土的施工质量。

Research purposes： The pier 5 of Tongling Yangtze River Bridge is located in the toe area oi the Yangtze River levee. During construction of the pile cap, the excavation work of the large foundation pit would no doubt cause big damage to the Yangtze River levee. Therefore, the reliable support way for the foundation pit had to be adopted, and the construction of the pile cap and the refilling of the foundation pit had to be fulfilled as soon as possible in order to restore the original function of the levee after construction of the pile cap. Research conclusions：After making the comparative analysis of various programs for pile foundation pit, the cofferdam bracing way with steel sheet pile in the single layer was adopted and with it the supporting structure facilitated the easy construction and mechanical excavation of borrow pit with feature that the construction could be conducted easily and rapidly to ensure the levee safety during construction period and the levee recoverability after construction. The concrete would be poured to the pile cap as a whole for one time. According to the simulation analysis result of the temperature field of hydration heat during the mass concrete construction period of the pile cap, the temperature reducing system with buried cooling water pipelines and the temperature monitoring system with electronic components were used to guarantee the concrete construction quality of the pile cap.