Cofra has started the installation of 45m deep drains in Hong Kong. The project is part of the Tuen Mun – Chek Lap Kok Link (TM-CLKL) from Tuen Mun to the new reclaimed Hong Kong Boundary Crossing Facilities area nearby the Chep Lap Kok airport. The project involves the installation of PVD within the tunnel alignment of two 5km long parallel subsea tunnels. The function of the vertical drains is to accelerate the consolidation of the subsoil prior to the arrival of the TBM’s.
Special about the project is a dense sand layer with a CPT cone resistance of 30 MPa at a depth of 25 to 30m below the surface that needs to be crossed. The installation equipment deployed is equipped with additional ballast and is successful in installing through this layer without predrilling.