ABSTRACT
The composite stratum encountered in Tunnel Boring Machine (TBM) tunneling presents great challenges and may be caused by potential hazards because of ground heave or ground settlements. In this study, the jet grouting (Rapidjet Method) and Tube-a-Manchette (TAM) with chemical grouting are employed to address composite stratum with varying properties, ensuring the necessary strength and waterproofing for TBM tunneling. Jet grouting enhances the grouting zone above the soil-rock interface, preventing the shield machine from shifting upward or causing ground collapse during excavation. TAM grouting around the jet-grouted bodies serves both for structural support and reducing soil permeability. The TBM launch and arrival in the study case proceeded smoothly, with a settlement of approximately 10 mm recorded 160 days after the shield passed through the improved composite strata by jet grouting. Therefore, meticulous planning of grouting methods can significantly reduce construction time and costs.
