ABSTRACT
Increasing urbanization has caused massive surge in development of urban underground infrastructure. Urban tunnels, however, are often prone to instability during their construction & their impact on existing infrastructure makes it an important design and construction aspect. Mechanised shield tunnels such as Tunnel Boring Machines (TBMs) are efficient, but an expensive solution to stability of urban underground tunnels yet owing to the risks associated due to inherent geological variability and uncertainties, there still lies a room for its optimization. Considering that, study proposes models for in-situ geotechnical & face stability predictions in mechanized soft ground tunneling using project TBM & geotechnical data considering machine-soil interaction i.e. load transfer mechanism during TBM advance. The established models have been further validated using statistical multi-parametric regression and hypothesis testing. The established models/correlations enable in-situ prediction/assessment of geotechnical parameters ahead of TBM in real time and would consequently enable their validation and excavation optimization to enhance the real time stability of urban soft ground mechanized shield tunneling. Real time geotechnical and face stability predictions would optimize operational cost & may even enable a degree of automation in TBM operations such as real time assessment of required face pressure, grout pressure, soil conditioning etc. as a function of the machine (TBM) parameters.
