厦门翔安海底隧道穿越富水砂层施工技术

 厦门翔安海底隧道是中国大陆修建的第一座海底隧道，全长6 051 m。隧道在海域浅滩段有约610 m穿越富水砂层，是该工程施工的难点之一，也是以往海底隧道施工过程中所未曾遇到过的，没有现成的施工经验可供借鉴。主要研究和介绍厦门翔安海底隧道穿越该段富水砂层的施工关键技术，即在地表采用地下连续墙和疏干减压井对砂层进行分仓隔水、降水，在洞内采用TSS小导管超前预注浆对砂层进行固结处理。研究和施工实践表明，该隧道在穿越海域浅滩富水砂层段施工过程中，采用洞外和洞内相结合的施工技术是可行的，操作简便、效果明显，对同类地质条件下的地下工程施工具有一定的借鉴意义。

CONSTRUCTION TECHNIQUES OF XIAMEN XIANG¢AN SUBSEA TUNNEL ACROSS WATER-ENRICHED SANDY STRATUM

Xiamen Xiang¢an subsea tunnel is the first subsea tunnel in mainland China，the length of which is 6 051 m. The length of the part of Xiamen Xiang¢an subsea tunnel in shallow beach is 610 m. There are no similar projects and experiences of construction for subsea tunnel to be referred. So the construction is difficult for the tunnel in shallow beach across the water-enriched sandy stratum. The key construction techniques for the tunnel across the water-enriched sandy stratum in shallow beach are introduced. The diaphragm wall and decompression well are used to resist and drain groundwater of sandy stratum. The ductule pre-grouting technology is used to reinforce sandy stratum in the tunnel. Integration of outside and inside construction technology of tunnel is adopted to cross the water-enriched sandy stratum in shallow beach. The practical result shows that the construction techniques are convenient and effective. The construction experiences are useful references to other underground engineering under similar geological conditions.