为有效解决强富水粉细砂地层隧道施工突泥涌水频发、进尺缓慢的难题，采用“顶管先贯通排水、后扩挖”的超前降排水技术对富水地层进行预降排水处理，以降低掌子面水压与地下水位。结合工程地质条件，针对第三系半成岩粉细砂层含水率高、胶结差、受扰动易流失及常规局部降排水难以截断水源等难点，提出顶管先行贯通、管内集中排水与垂直泄水管引排地下水相结合的降排水方案，并通过现场监测和三维渗流耦合数值模型，分析顶管顶进及降水过程中的地层响应。结果表明： 1）顶管超前降排水可显著降低强富水半成岩粉细砂层地下水位和孔隙水压力，有效减小掌子面突泥、涌水及坍塌风险； 2）顶管顶进后，管周形成卸荷松动区和不对称受力区，模拟所得位移、应力分布与现场应变和接触压力变化趋势基本一致，表明模型能够反映顶进过程中的主要力学响应； 3）降水后，顶管上部和下部孔隙水压力分别较初始值降低约97.4%和94.6%，现场渗压监测亦呈持续下降趋势，说明顶管贯通排水具有良好的降压效果，可为类似强富水半成岩地层隧道施工方案优化提供参考。

An advance jacking pipe drainage scheme is proposed to effectively address frequent mud and water gushing and the slow advancement of tunnel construction in highly water-rich fine sand strata. The scheme, “jacking pipe drainage and final expansion excavation”, is proposed to reduce the water pressure and groundwater level on the tunneling face. Particularly, a drainage scheme combining prior pipe-jacking connection, centralized in-pipe drainage, and groundwater discharge via vertical drainage pipes is proposed considering the engineering geological conditions, high water content, weak cementation, disturbance-induced particle loss, and difficulty in cutting off groundwater supply by conventional local drainage in the tertiary semi-formed silty fine sand strata. Field monitoring and a three-dimensional seepage-coupled numerical model are employed to analyze the ground response during pipe jacking and drainage. The results show the following: (1) The advance drainage scheme markedly reduces the groundwater level and pore water pressure in strongly water-rich semi-formed silty fine sand strata, effectively decreasing the risks of mud inrush, water inflow, and tunnel-face collapse. (2) After pipe jacking, an unloading-loosening zone and an asymmetric stress zone form around the pipe, and the simulated displacement and stress distributions are generally consistent with the monitored strain and contact pressure trends, indicating that the model can capture the main mechanical responses during pipe jacking. (3) After drainage, pore water pressures above and below the pipe decrease by approximately 97.4% and 94.6%, respectively, compared with the initial values. Furthermore, field piezometric monitoring shows a sustained pressure decline, indicating that jacking pipe drainage exhibits a favorable pressure-reduction effect and can provide a reference for optimizing tunnel construction schemes in similar strongly water-rich semi-formed strata.