November 22nd saw Shanghai Tunnel Engineering Co (Singapore) breakthrough successfully on the S$116M contract price TWRP Pipeline-C1 Tunnel in Singapore. Using a CRCHI (China Railway Construction Heavy Industry Corporation Limited) “Channel Express” slurry TBM to bore the tunnel, the breakthrough marks the successful completion of the 1.6km, 6m i.d. subsea water transmission tunnel, adding another important water transmission trunk line to Singapore.
The slurry TBM was launched on February 1st, with the machine achieving a highest daily advance of 17.6m, and a highest monthly advance of 289.6m through rock ground conditions.
The tunnel crosses the seabed for a considerable length under high water pressures, passing through mudstone, siltstone and sandstone with high rock strengths. There are also fractured zones along the tunnel alignment, making excavation challenging.
CRCHI’s R&D team designed the slurry TBM in accordance with the project requirements, configuring a number of intelligent management and monitoring systems to ensure safe, reliable and efficient tunnel excavation.
The TBM is equipped with advanced technologies such as high pressure main drive seal, jaw+roller two stage stone crushing, synchronous bi-component grouting, and a slurry circulation anti-blocking system. A telescopic camera, which was a ‘first use’ on the Singapore tunnel project, can monitor the inside of the main bearing and the excavation chamber by video, whilst the intelligent excavation management system can monitor the excavation volume in real time.
PUB TWRP Contract 1 comprises of a construction of the 1.6km, 6m i.d tunnel from the proposed Tuas Water Reclamation Plant (TWRP)/Tuas NEWater Factory to existing network in Jurong Island, construction of tunnel launching and receiving shafts and the installation of twin 2200mm and 1200mm diameter pipelines within the tunnel, pipelaying by cut and cover method, installation of pipeline appurtenances and construction of associated chambers.
It is one of the key infrastructure projects for Singapore’s National Water Agency, PUB.