Great World - Tunnelling Completes

RC works are in progress at the station and entrances, with pipe jacking works for the subway beneath Kim Seng Road underway. Both Changi-bound tunnels to Havelock and Orchard have completed, wrapping up tunnelling works for the project.

Breakthrough of Herrenknecht S-946 at Havelock Station on March 27, completing the Mixshield's second and final 500m Changi bound tunnel drive between both stations (Photo: Padraig Higgins, HK)

Great World Cast (IV)

Reassembly of the 2 Herrenknecht machines took place this quarter, nearly a year after the initial 2 launches were carried out. EPBM S-945 commenced on its initial drive back to Orchard, while the mixshield has almost completed assembly works and would begin excavation works next month. RC works are in progress at the station and entrances, with pipe jacking works at the subway beneath Kim Seng Road set to commence next month.

Entrance B & subway link roof slab cast

Great World Cast (III)

Excavation works have reached the formation level and the first zone of the station's underplatform level is being prepared for casting. Casting of the internal structure and external walls will proceed from here.

The first drives of both TBM S-945 & S-946 have completed and the replacement TBM shields have arrived at the site of both launch shafts in preparations for the relaunch.

T220 Great World station

Great World Excavation (III)

Excavation works are still in progress from the previous quarter towards the formation level. The replacement shields for both TBMs have arrived on site, and an acoustic shed is being constructed over both launch shafts.

T220 station top-down

May Tunnel Progress

Tunnelling works for Stage 1 of the line will be completed by next month with the final 100m long Woodlands bound tunnel being driven between LS2 and Woodlands South station. Concurrently, the twin TBMs from Springleaf will breakthrough at the RTS Facility Building, completing the longest mainline drives (2km) under the TEL project.

TEL 1&2 Tunnel Chart, May 2017

T206: Completed Changi Bound tunnel between LS2 and WDS under the second drive of TBM 4

Great World Excavation (II)

The concourse slab for the station has been completed and excavation works are now progressing down to the platform level. Bored tunnel works are underway in both directions towards Orchard and Havelock stations.

Excavation works proceeding down to the platform level

January Tunnel Progress

The 36th and third last TBM for the line was lowered down the Great World launch shaft earlier this month, with several more bored tunnels having been completed since.

TEL1&2 Tunnel Chart, January 2017

TEL3 Tunnel Chart, January 2017

Great World Cast (II)

Preparations for the heavy lifting works for the lowering of the project's first Herrenknecht TBM is underway now with the arrival of the 1200t Demag mobile crane. Lowering of the TBM will be completed by Christmas and tunnelling works for the Woodlands bound drive to Orchard station should commence around the later part of 1Q17. Excavation works for the station have reached the first basement (roof) level and casting works are underway.

Unveiling of EPBM S-945 and delivery of counterweights for heavy lifting mobilization

Great World Cast

Construction of the roof slab is taking place and is midway completed at the Great World station. Excavation works have commenced at the north end of the station, as well as the subway to River Valley road.

T220 Great World site

Great World Excavation

Lateral bracing along the first strut layer have commenced along the station box commencing the excavation process. The north launch shaft has reached the formation level and installation of the tunnel eye together with lowering and assembly of the EPBM will take place in the next quarter.

Completion of the diaphragm wall at Great World station and commencement of strutting for bulk excavation

Great World D-walls (VI)

The d-walling works for the Great World station have been ongoing for 18 months and are nearly completed. Excavation of both launch shafts are underway and segments for the 2 Herrenknecht TBMs are on the shaft surface.

Construction of the STP for the Herrenknecht mixshield at the south shaft

Great World D-walls (V)

Construction of the diaphragm wall is nearing completion at the Great World station. Both launch shafts have commenced excavation and shoring works, and Herrenknecht's slurry treatment plant is being assembled for the mix-ground tunnel drive to Havelock.

Commencement of excavation at the north and south launch shafts

Great World D-walls (IV)

Construction of the diaphragm wall at the Great World station has been ongoing for a year now. The completed d-wall of the south launch shaft is visible and excavation should commence soon.

Great World D-walls (III)

D-walling works continue at the Great World Station. A road diversion has been implemented along Kim Seng Road and Kim Seng Promenade for piling works of the entrance outside Great World City.

Great World Station

Traffic diversion outside Great World City

Great World D-walls (II)

D-walling works continues at the Great World site. The diaphragm wall works have now commenced on the north launch shaft (towards Orchard) in addition to the south launch shaft that had commenced a few months earlier. West of the T220 site, the Stamford Diversion Canal project is progressing ahead of the MRT project with the culvert excavated and a section of the roof already constructed.

The pedestrian pavement linking Great World City to Kim Seng Park behind Centennia Suites was closed in February for the canal project.

Aerial view of the Great World site

Great World D-walls

D-walling continues at the Great World site. A yard of pre-fabricated rebars can be seen to the south face of Yong An Park. The area around the south launch shaft remains the priority of the ERSS works.

Herrenknecht will supply an EPB and Slurry TBM under T220. The decision to procure an EPB TBM for the north drives to the Orchard Cripple Siding has been affirmed despite challenging mixed face conditions expected along the tunnel route.

Pre-fabricated rebar yard

Segregation of the PUB and LTA projects. The iconic Great World City is seen in the left background.

Great World - It's Beginning

Contract T220 is for the construction of the Great World station and 2 twin bored tunnels to Orchard and Havelock stations. The station is sited on an empty plot of state land once occupied by ERC Institute and the Ministry of Manpower. The buildings have since been demolished and works have begun at the site. The contract has been awarded to a joint venture between Tiong Seng and Dongah at a 65% to 35% stake ratio. These 2 companies have had common working experiences together while tunnelling under C913 of the Downtown Line.

Stamford Diversion Canal Contract 1

This is a civil contract by the Public Utilities Board (PUB) to divert water flow from the existing Stamford Canal by constructing a 2km drainage diversion tunnel to the Singapore River in an effort to alleviate flooding along Orchard Road. Contract 1 was awarded in May just 6 days before T220. Works have started on this contract and the Great World site is currently being shared between the two different projects from PUB and LTA.

Stamford Diversion Canal Phase 1

PUB and LTA project at the Great World site

Great World Station

The station will have 3 levels - An upper concourse, concourse and platform level. The upper concourse is a common subway level which will link all 5 entrances of the station. The station will be constructed top-down. Upon completion of the project, a new 400m long dual carriageway road connecting River Valley Road and River Valley Green will be built above the station.

Entrances C and E will be located on either sides of Kim Seng Road. The subway leading from the station to these 2 exits will be underneath the access road leading to The Trillium and Centennia Suites. As such, a 100m long pipe roof for trenchless construction of the subway will be adopted here. The subway leading to Entrance D on the opposite side of River Valley Road will be constructed using sheet piles.

A&A to existing POBs

2 Pedestrian Overhead Bridges will be altered under this project. The existing bridge located north of the station along River Valley Road will see one of its staircase being reconstructed whilst the bridge across Kim Seng Road to Great World City will integrate with Entrance C and have 2 new lifts added.

T220 Tunnel Chart

Tunnelling

2 Launch shafts will be built on either ends of the Great World Station. 1 TBM will launch out of the north launch shaft for a 650m double drive to the cripple siding at Orchard. The authority has given the contractor a choice of either an EPB or Slurry TBM to be used in this sector; and to justify for the chosen type. A cross passage will be constructed between GRW and ORC.

A slurry TBM will launch out of the south launch shaft for a 550m double drive to Havelock station. The tunnel alignment to Havelock runs beneath the recently completed Centennia Suites. The authority has imposed a no-pile zone during the construction of the apartment where the twin tunnels will cut under.

Gantry Crane over the mined shaft under Contract T2123, the first of such installed along the Thomson Line

Shaft at T2123 in proximity to the Alexandra Canal and Centennia Suites

Contract T2123

This is a civil contract awarded to Presscrete Engineering for the advanced works at the Great World site. The works involve constructing a small shaft, for the removal of abandoned piles (by mining) near Centennia Suites along the tunnelling route to Havelock. The demolishment of the 3 ERC and 8 MOM blocks were under this contract as well. Additionally, River Valley Green has been extended for site access to the Great World site.

Update Progress

Within 4 months of the award of contract, the Great World site has seen tremendous progress as compared to other contracts over a similar span of time, with the help of site clearing completed by the advanced works under T2123. Trench cutters and hydraulic grabs have arrived on the site. Guide walls for the d-wall excavation have been constructed at the south launch shaft. Silos have also been erected in the middle of the site and 12m high hoardings have been erected along the perimeter of the site.

Guide walls for the D-wall excavation of the launch shaft

Cross reference of the guide walls installed. Also shown is the mined shaft for T2123.

Package C Renders

 A/E Consultancy services for package C of the Thomson Line were awarded to Aecom and SAA back in 2010. Effectively known as Civil Team 3 as construction works gear up, the design boundaries span from Whitley Road to Havelock. Stations included in this section are Stevens, Orchard Boulevard, Orchard, Great World and Havelock. Napier station is not included inside the design package as it is separately designed by the client.

Photos courtesy of SAA

Contract Awards - T218, T220, T222 & T225

Today the Land Transport Authority announced the award of 4 contracts to build stations and associated tunnels. With the award of these 4 contracts, there only remain 3 such contracts for all stations to be awarded to contractors.

The first award is for contract T218, involving the construction of Orchard Boulevard station only. This contract has gone to local company KTC that is currently working on the Tampines Central station on the Downtown Line.

The first render issued of Orchard Boulevard station. It lacks certain details made more prominent in subsequent renders.

Tunnel Chart for TSL

Here's the tunnel chart organised into two sheets - stage 1 and 2, and stage 3. The exact number for T206 is not known at the moment. A total of 36 TBMs (excluding T206) are set be procured for the entire TSL.

Disclosed Acronyms:

SBAB - Sembawang Airbase

TGR - Tagore

5XO - TS05 Crossover

ULS - Upper Thomson Launch Shaft