中文摘要：

厦门市翔安隧道是我国首条海底隧道，其五通端右线隧道在采用CRD法施工过程中出现了较大的地表沉降变形，故欲更改采用双侧壁导坑法进行该段的施工开挖。结合现场实际施工和监测情况，就目前开挖段采用CRD法施工引发大面积地表沉降的问题给出了合理地剖析，寻求其可能发生的机制。同时，对目前更改后的双侧壁导坑法在地表沉降的控制效果方面进行了合理有效的分析和预测，得出2种不同施工工法在控制地表沉降及地表变形规律方面的差异，为现场实际施工提供借鉴，希望对以后相关工程具有一定的理论参考价值。

英文摘要：

Xiamen Xiang＇an subsea tunnel is the first subsea tunnel in China. The ground settlement became large when the CRD method was adopted on the right line in Wutong side. So it is determined to change the excavation method, i.e. the both-side drift method. Combined with the construction site and ground settlement, the CRD method is then adopted. The main purpose is to find the possible reasons that cause the large settlement. First, it is focused on the influence of the excavation, and it is seen that the displacement of the tunnel is the main reason that causes the ground settlement. Second, the decreases of the cohesion and friction of soils that are caused by continuous rainfall are contributed to the large settlement. Third, the ground surface of soils is changed into artificial landfill compared with the completed parts. At the same time, the controlling effects of ground settlement when the excavation way is changed to adopt the both-side drift method are obvious. The development of ground settlement with this method is different from that with CRD method, though the maximal settlement is all located at the top of the subsea tunnel. Finally, the difference between the two methods on the controlling effects of ground settlement and the regularity of the surface deformation are summarized. It can provide references to the construction of the project, and it can be adopted for similar projects.