Simplified Algorithm for Grouting Pressure and Grouting Quantity in Shield Construction

To reduce the impact on the environment around a shield tunnel, this study investigated a reasonable range of backfill grouting pressure based on the strength failure criteria for soils. A security parameter was introduced and a method of determining the optimal grouting pressure was proposed to ensure the safety of construction. Moreover, the relationship between the surface settlement and the theoretical grouting volume was derived based on the inhomogeneous distribution mode for loose ground. The results revealed that the maximum value of surface subsidence and the grouting amount have a linear relationship. This study proposes a simple method for achieving the optimal grouting amount based on field observation data.