Cut and cover

Abstract

The Chep Lap Kok airport platform has three cut and cover tunnels which provide vehicle and rail access. Construction methods and dewatering on these relatively deep excavations are detailed. One of the tunnels and its associated underground roundabout was constructed in CDG fill and rock fill and needed extensive grouting and dewatering. Another was built in a blasted trench on one of the original islands. The third tunnel for the light rail line spanned rock, reclaimed material, and deposits of fill and alluvial sands and clay. It features a raft foundation to prevent damage from differential settlement. The effects of tunnel construction on platform settlement are considered.