North Cross Expressway runs through the northern urban district of Shanghai with an approximate length of 19.1km. Several unprecedented difficulties were encountered during project execution, making the project an encyclopaedia in urban excavation. Brown was engaged to provide consultancy services for some of the challenging areas:
Over-Cross Existing Metro Line - The deep excavation (width 25m, depth >12m) in soft clay was in close proximity to existing bored tunnel of Metro Line 13, where the Expressway crosses over the tunnel after passing beneath Suzhou River.
TBM Tunnel Sharp-Curved Turning - A large portion of the alignment is curved with a minimum 500m-600m radius. This feature was especially challenging in selecting the TBM (15.56m diameter), the water tightness of the tail seal and segmental sealing gaskets, as well as the controls of construction risks.
