沈家门港海底沉管隧道工程北岸出入口原设计采用模袋砂围堰作为主体结构施工平台，由于在施工过程中受到地质情况、海水涨落潮水流、模袋砂刚性等因素影响，模袋砂局部产生沉降、位移。为保证沉管隧道出入口的顺利修建，通过对模袋砂围堰沉降变形原因进行分析，并对各种加固施工方案进行比选，最终采用钢管桩加固模袋砂。并对钢管桩加固模袋砂的工艺、过程及施工效果进行了介绍。采用钢管桩加固既可以发挥模袋砂施工工艺成熟、机械化程度高，又可以发挥双排钢管桩的整体性好、刚度大、抗变形能力强等优点，是柔性与刚性体的很好结合，取得了较好的经济效益和社会效益。

The entrance structure of Shenjiamen Harbor immersed tunnel is designed to be sandbag cofferdam. However, due to the effect of ground condition, the tide and the rigidity of the sandbag, displacement occurs to the cofferdam. In order to ensure the successful construction of the entrance structure of the immersed tunnel, the causes for the displacement of the cofferdam is analyzed and different consolidation options are discussed, which leads to the determination that steel pipe piles are used to consolidate the cofferdam. The construction technologies and effects of sandbag cofferdam consolidated by steel pipe piles are presented. The construction technologies of sandbag cofferdam and twin steel pipe piles can be used perfectly by using steel pipe pile consolidation technology. In the end, good economical and social benefits are gained. 