Installation & Monitoring Works of Downtown Line-2
The MRT's Downtown Line-2 was planned to be constructed from Gali Batu Area in the northwest to the city joining the Singapore MRT Network System. Kiso-Jiban Consultants (KJC) was awarded to undertake the Supply, Installation and Monitoring Works, Contract 9161C. This contract is for 3 Stations and about 5.0 km of Tunnels of the MRT Route from Beauty World Station, King Albert Park Station to Sixth Avenue Station under 2 different Construction Main Contracts C916 & C917, respectively.
The Subsoil's consisted of Fill Materials, Marine Clay, Granite and it's Residual Soils which posed challenges for the station construction and tunneling works. KJC's main role in this project is to monitor the installed instrument by manual and real time modes to give advance alerts on any unfavourable movement, heave, settlement, etc. to the Main Contractors for them to prepare for any precautionary measures.
The following were monitored -
- Temporary Strutted Excavation for Station Constructions, Launching & Receiving Shafts
- Tunnelling and Cross Audit Works
- Rock Blasting
- Cracks, Subsidence & Tilt Monitoring on the nearby buildings
In order to monitor the above performance and check the validity of the Geotechnical Design Prediction, some 5,700 sets of 20 different types of instrument were installed for this project. Some of them are manual monitoring types and some are with real time monitoring modes. Special Instrument like High Strain Vibrating Wire Strain Gauges, Automatic Tunnel Monitoring and In-place Horizontal Inclinometers were installed for real time monitoring.