Optimization of Ring Length, Staggered Joints, Alignment Negotiation, and Virtual Build of TBM Tunnels with BIM Modeling
The TBM-bored tunnels consist of tapered individual rings that are installed and rotated in a manner that straight and curved alignments are negotiated with the smallest deviation possible from the theoretical alignment. This deviation is an inherent feature of the segmental ring systems because a segmental ring is always built in the shape of a cylinder. Therefore, TBM guidance through a curved drive naturally produces minor deviations in line and grade that are restored using error minimization methods. If not prevented, crucifix joints present themselves when segment joints are aligned along a line in the longitudinal direction of the tunnel and can cause leakage. This paper describes procedures for optimizing ring length in tunnel curves and geometrical analyses and optimizing the staggered pattern of joints. The procedure is applied to the case of an ongoing light-rail transit tunnel construction. The virtual build of this segmental tunnel by negotiating all straight and curved drives with a BIM modelling is realized and summarized in this paper.