为分析厦门翔安海底隧道软基地段明洞不均匀沉降后的回填安全性和加固措施，采用荷载－结构模型进行研究。综合研究结论如下: 1）填土后明洞差异沉降预测值为80 mm，最小安全系数为2.11，虽然结构安全系数满足要求，但不均匀沉降将导致裂缝、错台及渗水，严重影响隧道使用功能和耐久性； 2）提出采用大孔径树根桩加固明洞衬砌两侧拱脚，TSS钢花管注浆加固仰拱中央，灌浆封闭裂缝，分层对称填土的综合处理方案； 3）经现场监测验证，预测沉降规律与实测吻合较好，加固措施成效良好，变形得到治理。

Stressstructure model is used to study the backfilling safety and reinforcement technology of the opencut section of Xiang’an subsea tunnel with differential settlement in soft ground. The study results show that the predicted value of the differential settlement of the opencut tunnel is 80 mm, and the minima safety coefficient is 2.11. Although the structural safety coefficient meets the requirements, the differential settlement may induce cracks, dislocations and water seepage, which has serious effects on the operation function and durability of the tunnel. Countermeasures, including reinforcing the arch feet by largediameter root piles, reinforcing the invert by TSS steel pipe grouting, crack sealing by grouting, and backfilling symmetrically and layer by layer, are proposed. The monitoring results show that the predicted settlement coincides well with the measured settlement, the reinforcement has achieved good effect, and the displacement has been brought under effective control.