ABSTRACT
This paper reports the waterproof grouting work carried out for the rescue of two TBMs stuck in the conglomerate boulder layer underlying the Taipei basin. The boulder layer lay shallowly at the job site from GL -1.5 m to -24.5 m. It consisted of densely packed boulders with average size of 30 ~ 40 cm and up. Both of the up-track and down-track TBMs were only able to advance a distance of 91 m (up-track tunnel) and 124 m (down-track tunnel) in the boulder layer before they became completely stuck in the ground. TAM (Tube-a-Manchette) grouting was adopted to grout the head area and the adjacent ground around the TBM. By careful execution of TAM grouting and systematically monitoring and analyzing the grouting pressure response, a good watertight grouted zone was constructed (GL -11.6 m ~ -24.4 m) under high groundwater level. Workers were safely sent out of the TBM to dig out a working space in front of TBM for the repair of worn out cutter bits and also for the structure reinforcement of the cutter head. After completion of cutter head repair, both TBMs were able to finish the tunnelling work in the boulder layer with no further problems.
