港珠澳大桥岛隧工程大面积深厚软基的加固处理，以及大回淤水道条件下管段柔性小接头处的预应力束筋将永久留置而不再在管节沉放落床、纵向沉降基本稳定后完全切断，形成半刚性管节。上述两者，是该工程项目施工中呈现的特色和亮点。此外，当日后长期运营中如管段小接头接缝仍出现有不测的拉开险情时，其应急工程处治对策也是必须事先妥慎考虑的预案。就上述各点问题进行了较为细致深入的探讨和分析。

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. 