Simulation Analysis of Shield Tunnel Segment Uplift Considering the Time-Dependent Viscosity of Slurry

A simulation method for segment uplift based on the direct force immersed boundary method is proposed. This method utilizes the immersed boundary method to simulate the coupled interactions between segments and grout slurry, employs a collocated grid finite volume method to discretize the control equations of the synchronous grout layer, applies the PISO algorithm to iteratively solve the flow field pressure and velocity, and uses the direct force method to calculate the forces on the Lagrangian points. Based on the forces on the Lagrangian points, the flow field forces and segment movements are updated. The simulation method is validated using field monitoring data from the Hangzhou Metro Line 7 project. The results indicate that the simulated time history curves of segment uplift displacement closely match the measured data, particularly showing a rapid uplift velocity in the initial stage, which gradually decreases and stabilizes as the grout slurry viscosity increases. Detailed data analysis reveals that the relative errors between the simulation results and the measured final uplift amounts are 9.02%, 22.22%, and 1.68%, respectively, validating the applicability of this method in simulating the segment uplift phenomena during shield tunnel construction. Furthermore, a comparison between the model considering the time variability of grout slurry viscosity and the analysis results without considering viscosity time variability demonstrates that the former more accurately reflects the actual uplift process of segments after disengaging from the shield tail, with calculated results being closer to the actual engineering conditions. The results indicate that the time variability of grout slurry viscosity significantly affects segment uplift in shield tunnel construction and is an important factor to consider in optimizing the synchronous grouting process.