By rosebell
With 7.22m-diameter CREC 1238 slurry TBM for Singapore’s Cross Island Line has passed its Factory Acceptance Test, and it is due to be deployed on the CR116 contract by a consortium of Soletanche Bachy International, Bachy Soletanche Singapore, Bessac and Gammon.
As the first double-shell shield CREG that has exported to Singapore, this machine is almost 60m long and weighs 866 tons. Considering that the machine will be commissioned and relaunched up to four times, the double-shell shield will facilitate disassembly in the tunnel.
Building of Ang Mo Kio interchange station and twin bored tunnels with a total length of 1.2km linking the future Teck Ghee and Ang Mo Kio interchange Sstations,are contents of CR116.
Also the location of intermediate launch shaft for the TBMs will be between the two stations.
While the main geology of path composed of Bukit Timah granite interspersed with fracture zones, the tunnel alignment has a minimum curve radius of 300m and also there are sections of Kallang strata (clay) and old alluvium strata, with water pressure up to four bars.
Additionall in order to allowing quick assembly and disassembly of the main drive, segment erector and back-up systems,As well as the double-shell shield, special auxiliary structures have been designed.
The main advantage of integrated pipeline bracket system is simplifying the assembly and disassembly of slurry pipelines in the shield. In addition, to overcome the challenges of launching the TBM in a narrow launch shaft, the pipeline extension gantry has been designed to be deployed in the launch shaft instead.
Moreover, TBM features staircases to access the segment erector’s working platform, symmetrically distributed slurry pipelines on the back-up system, mirror function and a towing force detection function for the pipeline extension device.
