Abstract:

The construction of the artificial island and immersed tunnel of Hong KongZhuhaiMacao Bridge has the following two features: 1) The deep, thick and largearea soft foundation of the artificial island and the immersed tunnel needs to be consolidated; 2) Instead of being cut off after the tube elements have been immersed and the longitudinal settlement becomes almost stable, the prestressed reinfored ties at the flexible joints of the immersed tube are kept permanently under serious backsilting condition. Furthermore, emergency countermeasures should be established in case unexpected edge opening occurs at the joints of the tube segments of the immersed tunnel in its longterm service life. In the paper, detailed analysis and discussion are made on the abovementioned points. 

Key words: Hong KongZhuhaiMacao bridge, artificial island, immersed tunnel, soft foundation consolidation, composite foundation, compaction sand pile, waterway with serious backsilting, semirigid tube, prestressed reinfored ties