“工厂法”沉管隧道早期性能的足尺试验研究

Full-Scale Test of the Early Performance of a Factory-Prefabricated Immersed Tunnel

由于沉管隧道管段体积大、结构形式复杂、施工工艺复杂,容易因温度、收缩以及约束等原因,造成管段结构在预制阶段出现危害性裂缝,进而影响结构的服役性能和耐久性能。文章依托在建港珠澳大桥沉管隧道工程实例,开展了足尺试验,对"工厂法"沉管管节关键部位的温度和应变发展实施了监测,分析对比了温度发展规律和应变发展规律。分析结果表明:在早期因混凝土水化热引起温度上升,整个管段结构膨胀受拉,温度到达峰值后逐渐下降,结构也收缩恢复;但由于混凝土自收缩等因素的存在,结构最终收缩受压。研究所提供的试验结果可作为深入进行数值分析的一个基础。

Due to large elements, complex structures and complicated construction technology, immersed tunnels are vulnerable to cracking under the influence of temperature and shrinkage and restriction during prefabrication, which are harmful to the serviceability and durability of the tunnel. This paper monitors the development of temperature and strain on the tunnel＇s key parts and compares relevant laws of temperature and strain development based on a full-scale test, using the immersed tunnel of the Hong Kong-Zhuhai-Macao Bridge Project currently under construction as an example. The results show that the immersed tunnel element structure will be subject to expanding and tensioning at the early age stage under a temperature rise induced by the hydration heat of concrete, then will shrink with the decrease of temperature after reaching the peak value; the element structure finally will be subject to compression because of autogenous concrete shrinkage.