由于海底隧道穿越复杂地层且承受高水头作用，盾构开舱的风险较一般陆域盾构隧道更高，选择一种安全、高效、经济的开舱辅助工法极其重要。依托厦门地铁3号线及2号线过海区间隧道工程实例，介绍冻结法、注浆加固结合衡盾泥护壁法在海底隧道盾构开舱中的应用； 基于场区水文地质特性及既往应用效果，对2种工法的地层适应性和安全性进行比较； 将开舱的工期及费用按照地层加固、刀具修复2个阶段进行划分，并分析其分布比例，建立单位修复耗时（耗资）与工作量之间的关系表达式。分析认为： 1）对于海底砂质土地层而言，既有注浆工艺的质量可靠性不满足常压开舱的要求，当地层稳定性不佳且开舱时间较长时，建议借助衡盾泥泥膜进行带压作业； 冻结法的地层适应性强，封水性好，在严密监控的条件下满足常压开舱要求。 2）冻结法在地层加固及解冻阶段的工期和费用较高，达到注浆加固法的1.6倍以上，但是舱内常压动火作业的效率为带压工况的7.1倍，综合比较，当刀具修复工作量较大时冻结法更具优势。

As the subsea tunnel is designed to pass through the complex strata and withstand high water pressure, the risk of shield chamber intervention tends to be higher compared to general landbased shield tunnels. Therefore, it is essential to develop a kind of safe, highly efficient and costeffective auxiliary chamber intervention technology. In this paper, typical technologies of freezing method and grouting combined with paste HDN film method are introduced and applied to the subsea tunnel projects on Lines 3 and 2 of Xiamen Metro. The recommended methods are compared in terms of adaptability and safety based on the hydrogeological characteristics and the previous application effect. The construction period and cost are divided into two stages, i.e. soil reinforcement and cutter repair, the distribution proportion of them is analyzed, and the relationship between unit repair time (cost) and workload is established. The analytical results show that: (1) With regard to the seabed sandy soil layer, the quality of the existing grouting technology fails to meet the requirements on reliability for chamber intervention under atmospheric pressure, and it is recommended to conduct hyperbaric operation with the assistance of paste HDN film in case of unstable strata and longterm chamber intervention; the freezing method demonstrates an excellent adaptability to sandy soil layer and a high level of watertightness, and which could meet the requirements of atmospheric operation under the context of close monitoring. (2) The construction period and cost required by the freezing method during the soil reinforcement and thawing stage exceed 1.6 times that as required by the grouting reinforcement method; while the efficiency of welding work under atmospheric pressure inside the chamber is 7.1 times that under hyperbaric condition; thus it could be concluded that the freezing method is more advantageous when the workload of cutter repair is high.