Ground Deformation and Control Techniques for Tunneling Using Ground Penetrating Shield Technology

Abstract:

Conventional shield tunneling requires the construction of launching and receiving shafts， which limits its applicability in densely built-up urban areas with restricted construction space. Ground penetrating shield technology （GPST） overcomes this limitation by enabling shield launching and receiving directly at the ground surface without working shafts. Taking the GPST tunnel project beneath West Gaoqing Road in Shanghai as the engineering background， this paper meticulously documents and analyzes ground deformation across different overburdens （from shallow to ultra-shallow） encountered by the shield. Subsequently， it discusses the underlying mechanisms and evaluates the control techniques. The results show that when the overburden thickness is less than 0.4 times the tunnel diameter， the tunneling-induced surface heave exceeds 40 mm， and mitigation measures are required. Grouting volume and grouting pressure are identified as the key factors governing ground deformation during GPST construction. The combined application of partial-span reinforcement and surcharge loading provides a noticeable mitigation effect， whereas the full-span reinforcement together with surcharge loading achieves optimal outcomes.