Friday, 2 January 2015

Piling at Bright Hill

Contract T211 has one of the biggest scope of works within the Thomson Line project, having an extensive cut and cover and bored tunnelling works. Aside from constructing the Bright Hill station in an awkward angle beneath the narrow Sin Ming Avenue, both ends of the station will see 3 launch shafts integral within several sections of cut and cover tunnels that stretches the entire site area up to 400m. For ease of interpretation, we have included a diagram indicative of the underground structures that are to be constructed at the site.

Recalling our previous update, works on the temporary sports facility for Bishan Park Secondary School (BPSS) were underway while Penta Ocean was preparing to realign Sin Ming Avenue. The sports facility have since been opened in November and works are underway to demolish the old facility, which sits right above the station box. Sin Ming Avenue has also been realigned closer to the south.

Plan diagram of Bright Hill
Progress Update
As of present no works have started on the ERSS of the station. The site is currently segregated into 2 sections on either ends of the station, where piling works have begun on the cut and cover tunnels and launch shaft. A load test is also being carried out at the site of Entrance B. Based on the process of works being carried out, the north side of the station will be piled first. A subsequent road diversion towards the north should be expected within the next 6 months for the south face to be piled.

Piling works at the north cut and cover site using a Buma casing oscillator C2000G - Buma CE Co Ltd
Tunnelling
Together with T202 and the JIPCT cable tunnel project, Penta Ocean placed a bulk order of 8 slurry TBMs from Kawasaki. 4 of the machines will be supplied for the T211 project, of which twin machines will launch from Sin Ming to Mayflower and Upper Thomson respectively.

The tunnels to Mayflower (MFL) will make a left curvature beneath the Bishan-AMK park, AMK Avenue 3 and go beneath the foundations of block 258 before docking into MFL. Along this tunnel route, the timber piles of the POB at Mayflower Sec are obstructing both tunnels and will have to be extracted. The POB should be demolished within the next few months.

An aerial view of the tunnel route to MFL from the north launch shaft. The said POB to be demolished, as well as block 258 can be distinctively seen along avenue 3 in the left background. Behind which lies the Mayflower Station.
Hoarded up site by T211 along Avenue 4, taken from block 258

Where the twin tunnels will go beneath block 258, essential ground improvement and structure stabilization works will have to be carried out prior to the arrival of the TBMs. In preparations for this, Penta Ocean has recently created a site beside block 258 (picture shown above). Glass prisms and automatic total stations have also been installed by the monitoring contract along the exterior face of block 258 throughout the month of December. Tunnelling works along this stretch are targeted to complete by Q3 next year.


North C&C tunnels beside the field at BPSS
North C&C tunnels site
Casing works - Buma CE Co Ltd
Casing works - Buma CE Co Ltd
Close up of the north C&C site. The completed BPSS temporary sports facility sits at the edge of the site
North C&C tunnels site
Plan diagram of Bright Hill pictured again for reference
Bright Hill Station, where no works on the ERSS have started. The new surface of the realigned Sin Ming Avenue can be distinctively seen and distinguished from the original alignment
South C&C tunnels
Load test at Entrance B beside The Gardens at Bishan
Load test at Entrance B
The remaining photos below are a drive through along the site on October 8 before the road diversion was implemented, from south to north.

October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue
October 8 - Drive through along Sin Ming Avenue

1 comment:

  1. I always wondered how cities picked road companies to construct roadways. I think it's amazing how they are able to work all that stuff out. It seems like it would be such a complicated process. http://www.eichler.net.au

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