Sunday, December 21, 2014

T206 Piles and Excavates

We gear up closer to the commencement of tunnelling works for the Thomson Line in this update. Excavation works for the Launch Shaft 2 (LS2) has just started after 6 months of drilling and piling. STEC has altered the design of the launch shaft from an initial rectangular box proposed by the A/E consultant into a double circular cell - similar to the proposed Dalvey LS at Stevens. The design omits the use of any temporary struts while a permanent concrete beam supports the compression forces of the shaft at its center. This is a significant milestone for the project and we expect excavation works to continue on throughout the next quarter. Works have yet to start on Launch Shaft 1.

T206 Tunnel Chart
Proceeding south, piling works are also in full swing at the Sembawang Airbase (SBAB), escape shaft and Mandai Depot.

Excavation of Launch Shaft 2
Piling works at the Sembawang Airbase C&C site and Avenue 12 Escape Shafts
Piling at Mandai Depot

Friday, December 19, 2014

Woodlands South D-walls

D-walling works for Woodlands South have commenced following the diversion of Avenue 1. 2 hydrofraise machines are currently executing the trenching works. More bentonite silos have arrived on the site and are awaiting to be hoisted up at the junction of Avenue 1/Drive 16.

Aerial view of Woodlands South, T205
3D layout of Woodlands South with respect to the first picture, personally drawn by us using Revit
Additional bentonite silos laying flat on the site 

Wednesday, December 17, 2014

Piling at Woodlands (2)

Piling works continue on at the Woodlands site with the 6 Bauers. The rigs are now spread out around the station box away from the crossover tunnel during the initial drilling. The site is viewed from a different angle - Causeway Point in this update.

A road notice has been put up informing motorists of the impending traffic diversions at the junction of Avenue 2/5 for the construction of the crossover tunnel, and a completion only in Q4 2017 when the tunnel is expected to have been backfilled. The diversions however have not started.

Monday, December 15, 2014

Woodlands North Terraced

We commence our 4th Quarter updates for the Thomson Line at the Woodlands North site. Penta Ocean has almost completed flattening the hill and a little valley has been paved where the rail structure is to be built beneath. The slope along the hills have been terraced into sections with much resemblance to the Caldecott site which shares a similar terrain. Piling works have commenced near the south crossover tunnel by the contractor, while preliminary soil investigation works have begun along the tunnel route from WDN to WDL station.

Woodlands North Site

SI works along the southbound tunnel route, opposite Republic Poly near the launch shaft

Tuesday, December 9, 2014

POB Progresses @ Napier

Following the successful beam launching works back in October, works to finish up the temporary POB have proceeded on with the completion of the bridge's roof as well as the staircase along the town-bound road. The bus stop at Gleneagles was relocated last month as well. The staircase on the opposite side near the US embassy is still being constructed.

Piling works continues to go on at the launch shaft and exit. 12m high hoardings are also being erected in front of Gleneagles where the former bus bay locates.

Progress of the temporary steel POB
Former bus bay has been demolished at Gleneagles where the 12m high noise barriers are being installed
Piling works continue at the launch shaft

Sunday, November 30, 2014

Spring Street Closes

Spring Street which serves as an in-going lane to Kreta Ayer Heights, will be temporarily closed from tomorrow onwards. As the road sits directly above the future Maxwell Station, the closure is necessary so that ERSS, excavation, casting works and movement of rigs and materials can be carried out swiftly with minimal disruption to the project.

The road will be reinstated towards the end of Q4 2018 when the station is expected to have been backfilled. During this interim, motorists will have to use Banda Street as a sole option of entering Kreta Ayer Heights. This is the second road closure under the T223 project following Dickenson Hill.

Rebars for the Diaphragm Wall lying on the site
Closed Spring St beside the completed T223 Site office

Wednesday, November 26, 2014

Piling at ULS

Coring and piling works have commenced at the Upper Thomson Launch Shaft (ULS) over the past month. At the site, 2 BG40s rigs and a mobile crane have progressively arrived while 4 pairs of bentonite silos have been erected. The permanent-temporary walkway pavements and site access around the launch shaft have also been fully done up by Sato Kogyo. The launch shaft is on track to be done up by the middle of next year and subsequently see its first Slurry TBM being launched out towards the end of 2015.

The photos consolidated in this update were taken on Oct 27, Nov 11 and Nov 26.

New site access to the south of ULS
Timelapse every 15 days

Sunday, November 9, 2014

Woodlands Avenue 1 Diverts

The third traffic diversion under T205 has been implemented over at Woodlands South this morning. This diversion shifts the existing southbound Avenue 1 closer to Christchurch Secondary, alongside the already-diverted northbound road which had been earlier implemented on Oct 6.

With both carriageways of Avenue 1 fully diverted, D-walling works for the north perimeter of the station will commence in full swing from now. A subsequent diversion of Avenue 1 to the north can be expected in 6 months for the d-walling works on the south perimeter. Upon completion of the ERSS we expect excavation works to begin by the first half of 2016.

New southbound carriageway diverted to the left. The station box will be located beneath the former road.

Thursday, October 16, 2014

POB Launches @ Napier

The temporary Pedestrian Overhead Bridge is successfully up at Napier Road following 2 nights of beam launching. The segment over the carriageway bound for Orchard was first launched up on Tuesday morning. The second segment of steel was then launched earlier this morning over the westbound road. The temporary bus bay and shelter along the eastbound road is almost completed, and would open anytime soon.

M&E works to the temporary bridge would take place together with the construction of the bridge's staircase from now. The new temporary bridge could possibly be operational by year end, following which the existing bridge would be demolished. This is the second POB to be demolished along the line.

Completion of beam launching along Napier Road this morning

The photos below show the progress of the beam launching throughout the week.

Wednesday, October 15, 2014

Gardens By The Bay

Concluding the final update for Q3 at the Marina Channel, preliminary site clearing and ground investigation works have commenced by the contractor at the Gardens by the Bay site. I will begin the 4th Quarter updates from mid-December; however occasional updates on recent developments will still be written over the next 2 months.

Contract T228 is for the construction of GRB station and twin tunnels across the channel to Marina East. Serving the other corner of the new downtown at Marina South, Gardens by the Bay station will be built beneath a future 2 lane dual carriageway road that will connect Marina Boulevard and Marina Gardens Drive. The road has yet to be named by the URA. With a fairly simple layout, the station will have a concourse and platform basement levels. Entrances A and B will be located on either sides of the new road. Entrance C to be linked by a subway will be located on a reserved portion of land between the Marina Barrage and Gardens by the Bay.

Entrance C to be built between the Marina Barrage and GBTB 

Tunnelling to Marina East
2 EPB Machines will be procured for this contract. The TBMs will be driven from a launch shaft east of GRB across the channel. A circular retrieval shaft - named Gardens by the Bay Marina East (GBME) will be built at the edge of Bay East under the contract. The GBME shaft will complement the docking of both the TBMs from GRB as well as the future E1 Marina East station under the Eastern Region Line project. T228 will handover the GBME shaft to the future ERL contractor throughout the whole of 2018 for the docking of the ERL TBMs before receiving possession of the shaft once again.  An escape shaft will then be constructed within the GBME shaft before it gets backfilled.

The tunnels will be driven straight down across the channel from the GRB launch shaft to GBME (foreground)
GBME Retrieval Shaft