为了解决过海隧道建设过程中安全快速穿越不良地质段的问题，依托厦门地铁3号线本岛至翔安过海隧道工程，针对其不均匀软弱围岩，对超前帷幕注浆方案进行研究。针对原“99孔-25 m”设计方案存在施工效率低下的问题，通过采取以“减少钻孔、配套优化”为主的系列优化措施，确定“56孔-25 m分段前进式”超前帷幕注浆方案： 1）径向加固范围为工作面及开挖轮廓线外5 m； 2）纵向加固范围为25 m； 3）浆液扩散半径为1.5 m； 4）注浆终孔间距为2.2 m； 5）使用普通硅酸盐水泥单液浆、超细水泥－水玻璃双液浆2种注浆材料； 6）注浆终压为0.5~1.5 MPa。结果表明： 方案优化后的扫孔效率提升至200 m/d以上，注浆效率提高3倍以上，综合施工速度平均达到1.72 m/d，为原计划的2倍，证明了优化方案的合理性和有效性。

In order to safely and rapidly go through sections with unfavorable geological conditions during the construction of subsea tunnels, advanced curtain grouting scheme for uneven weak surrounding rock of subsea section between Xiamen IslandXiang′an Subsea Tunnel on Xiamen Metro Line 3 is studied. The construction efficiency of the original design grouting scheme of "99 holes and 25 m of longitudinal reinforcement range" is low, hence, it is optimized by "56 holes, 25 m of longitudinal reinforcement range and sectioned grouting". The scheme after optimization includes: (1) The radial reinforcement range is 5 m away from the excavation face and contour line. (2) The longitudinal reinforcement range is 25 m. (3) The slurry diffusion radius is 1.5 m. (4) The distance of end grouting hole is 2.2 m. (5) Two kinds slurry materials, ordinary Portland cement and ultrafine cementglass water, are used. (6) The final pressure of grouting is 0.5-1.5 MPa. The application results show that: (1) The efficiency of hole sweeping is improved to more than 200 m/d. (2) The grouting efficiency increases by more than 3 times. (3) The average speed of construction reaches 1.72 m/d, which is 2 times the traditional construction speed. The rationality and effectiveness of the optimization scheme are proved.