Fairbank Silverthorne Contract 2 consisted of a series of shafts, connecting tunnels and collector system for the City of Toronto. The project is a part of the City’s Basement Flooding Protection Program and is located in the Fairbank Silverthorn area.
Due to extremely poor soil conditions and the requirement to tunnel through a shaft, a ground improvement system was required to allow the start of a TBM machine to penetrate the shaft without ground loss.
Maple Site Solutions Inc. was retained and in collaboration with the contractor’s engineer, installed a 45.0m deep secant wall thrust block system. This system allowed for the initial penetration through the existing shaft while their segments could be set into place to start the construction of the new tunnel.