Analysis of the impact of grouting reinforcement in muddy silty clay layers on tunnel horizontal displacement

To address the challenges of controlling tunnel horizontal displacement in muddy silty clay layers, this study takes the grouting reinforcement project for a shield tunnel on Hangzhou Metro Line 2 as a case study and investigates the impact of grouting technology on tunnel horizontal displacement. The results show that, within all monitored sections, the horizontal displacement of the tunnel segments significantly decreased after grouting, with an average improvement of 0.7–1.1 mm, indicating that grouting effectively enhanced the integrity of the surrounding soil and generally improved tunnel stability. In several sections, such as SSP425-SSP455 and SSP460-SSP490, some tunnel segments exhibited a change in the direction of horizontal displacement or a reverse adjustment after grouting, suggesting that grouting achieved proactive control of the tunnel alignment through optimization of the stress path. Although the response of different tunnel segments to grouting varied due to differences in initial conditions or geological characteristics, the technology was able to effectively control various types of deformation, demonstrating good adaptability and engineering robustness. The findings of this study can provide valuable reference for tunnel displacement control projects under similar geological conditions.