为解决注浆抬升技术整治地铁盾构隧道不均匀沉降效果不佳的问题，采用囊袋注浆方法进行盾构隧道抬升效果试验研究。先将浆液注入至隧道底部正下方的囊袋中，再对所抬升的隧道周围附加土压力与隧道变形进行量测。试验结果表明： 1）采用新式囊袋注浆法进行隧道底部注浆抬升，浆液不发生扩散，且在囊袋的约束下能够均匀分布，形状可控，可有效避免发生跑浆，隧道注浆抬升效果明显，隧道变形更稳定。2）相对单点注浆，多点囊袋注浆法对隧道周围土体产生的附加土压力变化更大，分布更加均匀。3）在囊袋注浆产生的附加土压力作用下，模型盾构隧道的竖向直径减小，水平直径增大，发生明显的横椭圆变形；与单点注浆相比，平均单个囊袋的注浆量变小时，采用多点同时注浆，盾构隧道变形更明显、更缓和。4）相对单点注浆，多点同时注浆对隧道的抬升量更显著，且降低管片错台、局部应力集中风险。因此，实际工程中建议考虑囊袋注浆法并采用多点注浆。
To address the ineffective performance of conventional grouting techniques in rectifying uneven settlement of metro shield tunnels, an experiment is conducted to evaluate the effectiveness of the bag grouting method for tunnel lifting. Grout is first injected into pre-positioned bags beneath the tunnel bottom; subsequently, the additional earth pressure around the lifted shield tunnel and the tunnel deformation are measured. The findings are as follows: (1) The novel bag grouting method used for uplifting the tunnel bottom prevents grout diffusion. When confined by the bags, the grout is uniformly distributed with a controllable geometry, effectively avoiding grout leakage. This method significantly enhances the lifting effect and results in more stable deformation. (2) Compared with single-point grouting, multi-point bag grouting induces larger variations in additional earth pressure around the tunnel, while producing a more uniform pressure distribution. (3) Under the action of additional earth pressure generated by bag grouting, the vertical diameter of the model shield tunnel decreases, whereas the horizontal diameter increases, resulting in pronounced transverse elliptical deformation. When the average grout amount per bag is smaller, the deformation of the shield tunnel becomes more evident and remains moderate when multi-point simultaneous grouting is adopted. (4) Compared with single-point grouting, multi-point grouting produces greater tunnel uplift and reduces the risks of segment misalignment and local stress concentration. Therefore, multi-point bag grouting is recommended for application in practical engineering.
