Diagnosis and Systematic Treatment of Seepage Hazards in Shield Tunnel in Water-Rich Gravel Layer Based on Sonar Seepage Method
摘要
Seepage in shield tunnels compromises structural safety and durability. This study investigates seepage in a tunnel beneath a water-rich gravel layer using sonar seepage detection to diagnose flow paths and sources. Results indicate that pit excavation-induced stratum unloading caused tunnel uplift, leading to segment joint opening and cracking at the edge of a grouted zone, enabling groundwater ingress. To address this, a systematic grouting strategy was implemented: epoxy resin was injected into ballast voids for high-adhesion sealing, segment joints were sealed with flexible epoxy to restore watertightness, and seepage channels were consolidated using cement-silicate dual-fluid grout for rapid setting and low permeability. Material selection considered adhesion, durability, and compatibility with concrete. Post-treatment verification confirmed no new leaks, stable deformation, and reduced groundwater velocity to 1.0 × 10−5 cm/s. The integration of sonar diagnostics with targeted material-specific grouting provides a scientifically grounded, effective solution. This work highlights the critical role of materials engineering in tunnel rehabilitation, offering a replicable framework for similar projects involving high-permeability strata.