盾构施工管片背后注浆是保证隧道安全、质量及控制地表沉降的关键因素，更与施工成本息息相关。大直径土压平衡盾构在富水基岩中施工时，由于其管片背后填充空间大、富水基岩地下水冲蚀，同步注浆效果差，注浆质量对工程安全、质量及成本的影响显得尤为突出。通过对长沙—株洲—湘潭城际铁路湘江盾构隧道的施工过程研究分析，针对大直径土压平衡盾构富水基岩地层管片背后注浆普遍存在的问题，采用“同步注浆、补充注入砂浆、二次补强注浆及封闭环施工”的施工方法，经过施工过程的调整和优化，确保了管片背后注浆质量的安全可控，有效地降低了施工成本，取得了很好的效果。

Backfilling grouting behind the segments is the key technology to ensure the safety and construction quality of the shieldbored tunnel, is the key technology to control the ground settlement, and is closely related to the construction cost. Xiangjiang tunnel on ChangshaZhuzhouXiangtan intercity railway is a large diameter shield bored tunnel crossing waterrich bedrock strata. Due to the big annular space behind the segment rings and the flushing erosion effect of the ground water, the simultaneous grouting carried out cannot achieve the expected result. In the paper, the causes for the problems in the simultaneous grouting are analyzed, and countermeasures including “simultaneous grouting, complementary grouting, secondary consolidation grouting and sealing ring execution” are taken and optimized during the tunneling. In the end, the safety and grouting quality are ensured and the construction cost is effectively reduced. 