沉管隧道整体式最终接头的地基刚度差异问题及处置措施

Solutions and problem of foundation stiffness difference of the integrated type closure joint of immersed tunnel of Hong Kong-Zhuhai-Macao Bridge

在港珠澳大桥,沉管隧道的最终接头在水下的浮力比相邻管节小很多,所以安装时对地基的初始压力是相邻管节的30倍,不处理就有差异沉降。为制定有效的处理措施,通过现场原位载荷板试验、陆上碎石基床压载试验,以及沉管管节沉降数据分析,证实了沉管基础"瞬时"沉降的规律;并基于此规律制定与实施了预压载、超载与接头底部密闭腔压浆的处理措施。

In the Hong Kong-Zhuhai-Macao Link( HZMB) immersed tunnel construction,the foundation pressure of the closure joint when touching down the ground is 30 times of that of the adjacent tunnel elements,as the buoyancy of closure joint is much less than its neighbors. Thus differential settlement exists. To make an effective counter-measures,the character of the 'instant settlement'of immersed tunnel foundation was proved by in-situ loading plate test,full-size load test on land,and the observation of settlement of the existing tunnel elements;based on the settlement character,the measures of preloading,surcharge and sealed grouting below the connection parts were performed.