Shenton Way - Tunnelling Completes

Bored tunnel works for the T225 project completed in the early hours of today with the docking of TBM 2 at Maxwell station. Tunnelling works were unique in this project due to the stacked configuration of the 2 launch shafts, one of which is within the permanent structure of the station. Geological constraints were also experienced beneath McCallum St resulting in prolonged delays and the eventual re-sequencing of the TBM drives.

T225 is the 3rd last team to complete tunnelling works for the line, ahead of T222 later this month and subsequently T216 in Q4.

Upper/Changi Bound tunnel towards Maxwell completed by TBM 2

Shenton Way Cast (IV)

Casting of the internal structure within the station is ongoing concurrent with the excavation and RC works at the unpaid linkway. Excavation works for TBM 1 has resumed with a further 100 rings advanced this quarter. In view of the lost time caused by the challenges at McCallum St, the project team is re-using TBM 2 to complete the Changi bound tunnel towards Maxwell. The TBM commenced mining works today, making it the 3rd last TBM relaunch along TEL1-3.

Shenton Way Station

Shenton Way Excavation (III)

Bored tunnelling works between Marina Bay and Shenton Way stations have completed with the second and final drive of TBM 2 docking at the upper platform of the station. FSC works have commenced for the lower tunnel. The porous geological conditions around the former shoreline beneath Shenton Way has created an ongoing challenge for TBM 1 since its launch in April, which has progressed little since its main drive conversion.

Bulk of the station's structure has reached the under-lower platform level, with a final zone of excavation works due for completion within a month. Excavation and shoring works have commenced at entrance C.

Completion of 144-bored pile linkway between the station, entrance C and Asia Square

Shenton Way Excavation (II)

Structure of the station has now progressed to the underplatform level of the Changi bound platform. Conversion to main drives are underway for both TBMs.

Shenton Way station

Shenton Way Cast (III)

Excavation works have reached the plantroom level and is progressing down to the upper platform level. Assembly of TBM 1 has completed and commencement of tunnelling works to Maxwell are slated to begin tomorrow.

Concourse slab completed at the station

Shenton Way Excavation

Excavation works are in full swing at the station box, with varying progress between the concourse and plantroom level (B2/B3). Excavation of LS3 is still in progress, and LS4 is being handed back to Taisei for the upper tunnel slab casting works.

Installation of gantry cranes for top-down construction of the station

November Tunnel Progress

Tunnelling works for the line have been ongoing for 15 months now. 11 bored tunnels have been completed.

TEL1/2 Tunnel Chart, November 2016

T202 - Breakthrough of TBM 2 at Woodlands Station on October 10. This is the first contract to complete all bored tunnel excavation

Shenton Way Cast (II)

The first zone of roof slab has been completed and casting of zone 2 is in progress. Excavation works for the 3rd zone are underway. 2 gantry cranes have been assembled at LS3.

Roof slab casting works

July Tunnel Progress

Tunnelling works are underway along all the projects along stages 1 and 2 of the line, with the first slurry TBM for the T211 project launched at Bright Hill this week. 5 bored tunnels have been completed by the first half of the year and a further 5-8 tunnels are envisaged to complete by year end.

TEL1/2 Tunnel Chart, July 2016

T206 - Launch preparations for the second drive of TBM 4 for reception tunnel 1 at Sembawang Airbase C&C (Photo credits: LTA)

Shenton Way Cast

Excavation of LS3 have commenced within the Shenton Way station, of which the bored pile works are still progressing. The roof slab is being prepared for sequential casting and rebar installation is in progress. TBM 2 has commenced its initial drive at LS4 following the commencement of tunnelling works earlier this month.

Top-down view of the station box with its roof slab progressively being constructed concurrent with the bored pile foundation works

May Tunnel Progress

The second bored tunnel was completed at the T208 project earlier this month, lining the Changi bound tunnel between Tagore and Lentor. Despite NFM's inagurual entry into the Singapore metro tunnelling market, the french-manufactured machine has set a new record of excavating and lining 23 rings (32.2m) in 24 hours, in addition to completing a 100-ring excavation within 6 days in March. TBM A will now commence dismantling and be retired after having completed the 8-month tunnel drive.

Completion of TBM A drive (T208, John Holland)

Piling at Shenton Way

The diaphragm wall of the Shenton Way station has completed and bored pile works for the station's foundation have been ongoing through the first quarter of the year. Excavation works for the station and integral launch shaft 3 will commence by the middle of the year. LS4 at Marina Bay was handed over to the STEC team after CNY where formation of the tunnel eye preps up for the TBM launching.

Bored pile works at Shenton Way

Shenton Way D-walls (IV)

The diaphragm wall at the Shenton Way station is nearly completed, and construction of the bored piles as well as grouting is being carried out in tandem. STEC have constructed the TBM muck pit and commissioned 2 gantry cranes adjacent to the Marina Bay launch shaft while awaiting possession of the launch shaft which has yet to be handed over by the Taisei team.

Shenton Way D-walls (III)

The diaphragm wall for the Shenton Way station is nearly completed and excavation works are slated to commence by the beginning of next year. Grouting is taking place across the station box. The diversion of the monsoon drain across the central linear park has also been completed.

The tunnel drives for this project have been altered from the initial A/E consultant specifications. Each TBM will now complete the respective upper and lower drives between 2 stations as opposed to completing the tunnels to Maxwell first, before relaunching both machines at Marina Bay.

Marina Bay - Shenton Way Tunnels

Excavation of the launch shaft at Marina Bay is completed and the first STEC EPB TBM is slated to arrive at the site upon handover from Taisei around the first quarter of 2016. Mining of the lower Woodlands bound tunnel should commence by the 2nd quarter thereafter. As of now, ground improvement works continue to take place along the tunnel route beside the Marina One project. Updates on the launch shaft at Marina Bay can be found here.

Shenton Way - Maxwell Tunnels

A section of McCallum St between Boon Tat Link and Robinson Road was closed on September 6 as the project team continues the advanced preparatory works ahead of the TBM launch. An access shaft will be constructed beneath the road to facilitate protection works to the adjacent operational EWL tunnels beneath Robinson Road. The road will reopen by the 4th quarter of 2016 - around the time when the second TBM is expected to launch.

Shenton Way D-walls (II)

The project team at Shenton Way has closed the section of Park Street behind Asia Square to facilitate the Diaphragm wall works for the station box. Several modifications have been made to Marina View to maintain traffic access to Tower 2 of Asia Square.

Excavation of the temporary culvert beneath the linear park is complete, while works are still on going at the southern section near the interface of the station box. D-walling works continue at the launch shaft.

Closed section of Park Street

Modifications to traffic access at Tower 2

Demolishment of Golden Bridge

Today marks the end of the Lunar New Year holiday during which demolishment works for the Golden Bridge over Shenton Way were scheduled and spearheaded by STEC and the Land Transport Authority from the T225 project. This is the 3rd overhead pedestrian bridge to be removed for the Thomson Line works. A separate project will oversee the construction of a replacement bridge that will link OUE Downtown & V on Shenton in 2017.

Shenton Way will reopen to public from tomorrow. Photos in this update were taken by Project Director Khor of STEC.

Shenton Way D-walls

D-walling works commences at the Shenton Way Station. Several ancillary works are also underway to facilitate the construction of the station and bored tunnels.

Drain Diversion

An existing drain runs north-south beneath Asia Square 2, cutting across the proposed station box. East of Asia Square, sheet piling works are on going along the future Central Linear Park for the new temporary box culvert drain. The curvature in the canal design takes into consideration the existing showroom of the Marina One, as well as to avoid the future 2 station entrances along the park that will be constructed under the very same project. The drain will be reinstated at the end of the project.

Demolishment of Golden Bridge

A new signalized junction of Shenton Way & McCallum Street had been operational since December 12 to replace the Golden Bridge which is in the process of demolishment. The demolishment works have already commenced earlier this month, with completion slated by February 22. During this interim, several full-day lane closures along Shenton Way and McCallum Street will be implemented.

T225 Shenton Way

Temporary 8m box culvert monsoon drain diversion

Shenton Way Begins

Contract T225 is for the construction of Shenton Way station and 2 adjacent twin bored tunnels connecting Maxwell to Marina Bay. The station is located along Park Street on state land south of Asia Square Tower 2.

Shenton Way Station

The station will have 5 levels with formation at about 40m below ground level. The levels are - Subway Linkway (B1), Concourse (B2), Plant Rooms (B3), Upper and Lower platforms (B4/B5). There will be 3 entrances. The main entrance A with vent shafts integrated will be located south of Park Street. Entrances B and C will be located along the future Central Linear Park - empty patches of reserved land for recreational activities to be extended south from the existing Lawn@Marina Bay.

The station will also be directly connected to neighbouring developments such as Asia Sqaure, V on Shenton and the Marina One through the subway link to be part of the future Underground Pedestrian Network (UPN).

Existing site hoarding (yellow), proposed station box (blue)

Tunnelling
2 EPB machines will be self manufactured by STEC under this contract. The 2 TBMs will do an initial launch from Shenton Way towards Maxwell before dismantling and relaunching back for the second drives from Marina Bay to Shenton Way. The launch shaft at Shenton Way will be integral to the station box due to space constraints. The launch shaft at Marina Bay will be constructed by T226 and will require a handover process.

Both tunnel drives are in a stacked configuration. For the drives to Maxwell, the Golden Bridge across Shenton Way will be demolished for the extraction of piles along the tunnel route. Further down McCallum St, 2 temporary access shafts will be built for the installation of protection works to the existing EWL tunnels running under Robinson Road. Temporary closure of McCallum St can be expected during the construction.

T225 Site Office along the future Central Linear Park

Update Progress
The structure of the site office is completed and fit out works are underway. Casting of the surface slab is taking place. A hydrofraise, piling rig and 2 crawler cranes currently sit on the site. The bentonite plant and silos are located south of the site.

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.

Shenton Way pre-construction

Several photos showing the area where Shenton Way station will eventually come up.