Analysis of convergence deformation remediation of shield tunnels by lateral grouting

Grouting is recognized as an effective method for remediating convergence deformation in shield tunnels. However, simple and effective theoretical calculation methods to guide on-site construction are still lacking. By constructing a mechanical analysis model of tunnel deformation induced by horizontal lateral grouting, this study derives a mathematical expression for tunnel longitudinal convergence deformation caused by single-hole grouting. This analysis is further extended to cases involving double-hole and continuous multi-hole grouting on the same side. The theoretical method is validated by field monitoring data and numerical simulation, confirming its rationality. Under grouting pressure, the tunnel's transverse convergence deformation displays a “π”-shaped distribution along the longitudinal axis. This deformation shows a negative correlation with tunnel-to-grouting hole spacing and burial depth, and a positive correlation with grouting pressure. Tunnel stiffness and soil cohesion have minimal impact on the convergence deformation. The research provides a reference for predicting tunnel convergence deformation resulting from grouting activities.