Nicoll Highway collapse
Coordinates: 1°18′9.16″N 103°51′57.47″E / 1.3025444°N 103.8659639°E
The Nicoll Highway collapse was a construction accident that occurred at approximately 3:30 p.m. Singapore Time (UTC+8:00) on 20 April 2004 in Singapore when a tunnel being constructed for use by MRT trains collapsed. The tunnel was part of the construction of the underground Circle Line, near Nicoll Highway station. The supporting structure for the deep excavation work failed, resulting in a 30-metre (100 ft) deep cave-in that spread across six lanes of Nicoll Highway. The collapse killed four people and injured three. The accident delayed the construction end date for the MRT station.
Investigations and probes into the collapse commenced immediately. It eventually was found that the most apparent cause of the collapse was that the retaining wall could not handle the stress of holding up the tunnel, forcing it to give way. This occurred near the Nicoll Highway MRT station under construction along the Circle Line and near the Merdeka Bridge.
The accident left a collapse zone 150 m wide, 100 m long, and 30 m deep. Four workers were killed, with three more injured. Steel beams were twisted, with two construction cranes being swallowed up. A substantial chunk of the main highway running over the tunnel was also knocked out.
The rescue efforts were called off on 23 April 2004 because of the low chance of survival by that point, as well as danger to the rescue teams. There was also the increasing need to stabilize the ground around the accident site to reduce the risk of further collapses. All six lanes of the Nicoll Highway were heavily damaged, rendering the road unusable. The highway re-opened on 4 December 2004 after reconstruction efforts.
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