Detection of Tunnel Squatting along CTE, MCE and KPE Road Tunnels and Enhancement of Road and Subway Tunnel Safety Standards

Mr Victor Lye asked the Acting Minister for Transport (a) whether LTA has detected tunnel squatting, in which tunnel linings are deformed from compression, along road tunnels such as the CTE, MCE and KPE; (b) whether current coordination protocols and monitoring of construction activities near MRT and road tunnels are sufficient; and (c) how does Singapore's road and subway tunnel safety standards compare with those of other countries that experience tunnel squatting.

Squatting is more likely to occur in circular bored tunnels running through softer ground. Road tunnels in Singapore are rectangular and constructed using the cut-and-cover method and are thus less susceptible to tunnel deformation. The Land Transport Authority (LTA) has not detected any significant deformation of our road tunnels.

Singapore's standards for the construction and monitoring of rail and road tunnels are aligned with international best practices and are comparable to the standards of other cities with extensive tunnel networks, such as Hong Kong, Shanghai and Tokyo.

Comprehensive protocols are in place to protect our rail and road infrastructure from nearby construction activities. Developers must obtain LTA's prior approval for works. Where such works are in close proximity to tunnels, developers must deploy monitoring instruments and carry out regular inspections. Additionally, LTA audits developers to ensure that such monitoring and inspections are properly implemented.