Piling at Mayflower (II)

Bore piling works continue at the Mayflower site. A second traffic diversion was implemented mid-December at the junction of Street 11, swinging the twin carriageway of Avenue 4 towards the west. The diversion will last for 2-3 months. Instrumentation works have also begun with tiltmeters installed along the columns of the HDB flats surrounding the site.

Penta Ocean from the neighboring contract T211 is also preparing a small site south of Mayflower for preparatory works of the 2 TBMs that will be driven from Bright Hill, both of which will go beneath the foundations of Block 258. More will be shared in the T211 update.

December 24 - Panorama of Mayflower, T210

December 24 - Close up of traffic diversion 1A

Lentor D-walls & Piles

D-walling works at Lentor has commenced this quarter. Close to Yio Chu Kang road, the team is in the midst of constructing the sheet pile for the subway that will link to the station entrance at Calrose. Sheet piles are a favorable method of constructing an ERSS due to the time efficiency in installation and transportation. The interlocking steel segments are also earth tight and water resistant. This method is hence commonly used in shallow linkways and cofferdams.

We expect the completed section of sheet pile to be subsequently decked over by a second and more permanent traffic diversion at the junction of YCK/Ave 4/Lentor Drive next year. This is for the construction of the remaining section of subway beneath the existing diverted road, and subsequently the construction of the entrance at Calrose itself. This diversion would then probably last until the completion of the project.

Sheet piling for the subway leading to the station entrance at Calrose

Panorama of 5XO

At the 5XO site, Avenue 4 was diverted at the end of Q3 and with the site cleared, hoardings are going up along the west side where sheet piling works have commenced. D-walling works should commence from next month as well. To the east, silos and a desander plant have been assembled to support the impending D-wall construction.

Project notice for 5XO (transcript):

- Identified trees along AMK Avenue 4 have been fully removed to facilitate crossover tunnel box construction (5XO)
- Road diversion works at 5XO will be carried out in 2 stages. Traffic Diversion 1 completed on 29 September 2014.
- Traffic diversion 2 at the junction of Avenue 4/5 are planned to commence in early January 2015.
- Tubular pile, steel deck and RC drain has been constructed close to Block 643
- Sheet pile works at Blk 613,614,615 has commenced from mid Dec and will last for a duration of 3 months.
- Installation of monitoring instruments along the ground and buildings
- D-wall works along Blk 613/4/5 planned to commence from end November (delayed)

Tagore Piles & Excavates

Tagore is currently leading in progress due to the large number of equipment brought in by Leighton-John Holland. The ERSS along the south side of the station and launch shaft has completed and excavation works have begun, with the first layer of struts have been installed. Ground treatment works are being done beside the launch shaft as well. Piling works continue at the north side and a desander plant is being constructed next to the Tagore site office.

NFM Technologies has been chosen as the manufacturer to supply 3 Slurry TBMs for T208. Upon completion of the first tunnel towards Lentor, 1 machine will be redriven in the direction of Springleaf. Pigott Shaft Drilling shall supply the slurry treatment plants for the 3 slurry shield machines.

9 piling rigs, 3 crawler cranes and a mobile crane mobilized at the Tagore site

Mock up of 1 one of the 3 NFM Slurry TBMs to be used for T208

Springleaf - Preparations to Divert

At the Springleaf site, construction of the ERSS on the west end of the station has completed. The project team is now preparing to stage a traffic diversion along Upper Thomson Road to construct the remaining portion of the station's retaining wall which lies below the existing road. This impending diversion is expected to be a permanent-temporary one, whereby it will last through most of the duration of the project. The diversion should take place within the next 2 months.

Due to the presence of a launch shaft at the north end that needs to be constructed and handed over to Shimizu of the neighboring contract T207, there is an urgency for the shaft to be done up swiftly. The handover is anticipated to take place around the middle of next year.

D-walling & Piling activities back in October

Preparations to divert Upper Thomson Road (Dec 22)

Facility Building Reduces Level

Slope treatment works continue at the RTS Facility Building. The site is currently being excavated to match the reduced level of the Seletar Expressway. Upon completion, piling works will commence on the RTS shaft and subsequently excavation. The site office has also been completed along Upper Thomson Road beside the Springleaf site. The escape shaft site between the RTS and SBAB has been cleared, though no works on the ERSS have commenced. 4 Japanese EPB machines have been said to be procured for this contract, instead of the initial recommendation of slurry TBMs.

Excavation of the RTS Facility Building site

Bentonite Plant

T207 Escape shaft south of SBAB and MDD

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. Kori has been subcontracted by STEC for shoring works under T206. In addition, Kimlun of Malaysia will be supplying the precast tunnel segments for the 10 tunnels within this contract.

Excavation of Launch Shaft 2

Piling works at the Sembawang Airbase C&C site and Avenue 12 Escape Shafts

Piling at Mandai Depot

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 

Piling at Woodlands (II)

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.

Woodlands North Terraced

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 at the launch shaft by the contractor, while preliminary soil investigation works have begun along the tunnel route from WDN to WDL station.

Kawasaki will be supplying Penta Ocean's Contract T202 with 2 slurry TBMs for the drives from Woodlands North to Woodlands Station, while Pigott Shaft Drilling will supply the slurry treatment plants for the 2 machines.

Woodlands North Site

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

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

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

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

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.

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.

Gardens By The Bay

Preliminary site clearing and ground investigation works have commenced by the contractor at the Gardens by the Bay site.

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

An EPB Machines will be procured for this contract. The TBM 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 the TBM 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

Marina South Hoards Up

Contract T227 is for the construction of Marina South station, twin bored tunnels north to Marina Bay and a section of cut and cover tunnels from Marina South to Gardens By the Bay. Designed to serve a corner of the future development at Marina South, the station is located at an angle parallel to the MCE under the proposed extension of Marina Mall (road). The design takes into consideration the future Singapore Underground Road System (SURS) which will run beneath Marina Mall such that the concourse & platform level would not be obstructing the future road tunnel.

The station will be 20m deep with 4 basements - UPN linkway (B1), Concourse (B2), Mezzanine (B3) and Platform (B4). Entrances A,B and C will be located along Central Boulevard whilst Entrances D and E will be along Marina Boulevard. 5 vent structures will be built for the station.

Hoardings partially hoarded up around an empty field where the station will be

Bored tunnels
An EPB TBMs will be double driven from a launch shaft at Marina South 850m to Marina Bay. The tunnels will be in a semi-stack configuration when it undercrosses part of a designed pile-free zone of the Common Service Tunnel (CST) Phase 3B that has been specially catered for the tunnels to be bored through. 1 semi-stacked cross passage will be built south of the CST intersection. This is the 48th and final CP to be built within the TSL tunnels.

Cut and Cover tunnels
The tunnels connecting Marina South to Gardens by the Bay (GRB) will be constructed fully by open cut. This is for the construction of a cripple siding and crossover track between both stations. 650m long, the C&C portion is also the 5th and final Temporary Staging Area (TSA) site along the line.

Curvature in the site clearing can be seen for the future Cut and Cover tunnels to GRB

Ccontract boundary between T227 and T228

Update Progress
Being under the last batch of contracts to be awarded, minimal site clearing and hoarding works can only be seen at this point in time. Yongnam had also recently been awarded the subcontract for shoring works under T227.

Marina Bay Encloses

Contract T226 is for the construction of the new Marina Bay station. The excavated portion will be predominantly divided into 2 sections segregated by the existing North South and Circle Line tunnels. The excavated portion in the south will be for the main station box; the north portion would be for the TBM launch shaft for T225 and an access shaft to facilitate mining activities to link the 2 open cut areas. Extensive underpinning works to the existing RTS is required for the mined section. This is where the ground freezing is designed to be executed.

The new TSL Marina Bay station will have 3 new entrances and 5 basement levels with a formation level 38m deep. Entrance A (integrated with vent shaft 1) and Entrance C will be opposite the existing CCL entrance along Bayfront Avenue and Park Street respectively. Entrance B is located at the future intersection of Sheares Avenue and Park Street.

Existing RTS in Orange/Red, Existing site boundary in yellow, Proposed station box in cyan (Mined tunnels in blue)

Transfers and A&A to Existing RTS
In simplicity, 2 new dedicated connections will be made to the TSL from the existing NSL and CCL stations. The NSL linkage will be an open cut section parallel and west of the NSL station box along the former Marina Station Road. This linkage will be on the level as the NSL concourse B1.

The CCL linkage to be located east of the existing CCL station  along Bayfront Avenue will offer an unpaid and paid section. Located on the same level as the CCL concourse, the design makes use of existing knock out panel provisions made into the CCL station. The south knock out panel will feature the paid link (hence a reconfiguration of faregates within the CCL station). The north panel will feature the unpaid link.

T226 Taisei's site office and LTA's TSL Civil Team 4 project office completed to the west at 20A Park Street

Update Progress
The last 3 months have been spent on site clearing, as well as minor ground improvement works around the site area. 2 clusters of silos have been hoisted up south and west of the proposed station box. 4 crawler cranes, 2 trench cutters and a piling rig has been assembled on the site however no excavation has been taken by the d-wall machines yet.

With the recent closure of the former Marina Street and Marina Station Road, the site area has now been fully enclosed with the old roads cleared of traffic. The site office has been completed around 2 months back. The same building will house the project office of LTA's Thomson Line Civil Team 4. Here's a timeline of progress over the 3rd Quarter.

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.

Maxwell - It's Beginning

The Maxwell station under T223 will have 3 levels. The formation level is proposed to be 31m beneath the surface of Neil Road. The station will have 3 entrances. Entrance A will be built infront of Kreta Ayer Heights; Entrance B will be at Maxwell Food Centre and Entrance C will be located at the Chinese temple.

Following the closure of Dickenson Hill, the bentonite silos have been erected and a treatment plant has been assembled. A hydrofraise trench cutter has been brought to the site. The site office is currently being built in the center of the site. Several traffic diversions for Neil Road has been planned and will be executed in phases.

Bentonite plant and silos

T223 Site office in the midst of construction

Outram Park Assembles

Contract T222 is for the construction of Outram Park station and 2 twin bored tunnels to Havelock and Maxwell. The station is situated on an empty plot of state land north of the existing East West Line. The contract was awarded to Daelim Industrial. They have previously worked under Contract 487 of the Marina Coastal Expressway and this is their second project for the Client.

Site overview

Proposed TSL box parallel to the existing East West line (left)

Outram Park Station
The new station will have a very similar layout to its EWL counterpart. There will be 3 levels - a Concourse, Platform and Transfer level. An additional 2 entrances will be built along Outram Road to complement the existing interchange. Entrance A will be located near Pearl Bank, while Entrance B provide doorstep connectivity to the Health Sciences Authority. The station will be constructed top-down.

A&A to existing RTS
There will be an overhaul in the linkage design within the existing interchange. The new changes include:
- 1 new dedicated NEL-EWL paid link with 4 travellators
- 1 new dedicated NEL-TSL paid link to be extended from the existing NEL-EWL linkage
- 1 new EWL-TSL paid link to be constructed beneath both platforms on the transfer level. 2 new escalators will be installed down from the west end of the existing EWL platform for this linkage.
- 1 new unpaid link between all 3 lines to be constructed on the concourse level with 4 travellators

Outram Road which would see intensive phased traffic diversions to build the new linkages

New Entrance B to be built infront of HSA and enhance connectivity to the interchange station

Tunnelling
2 launch shafts will be constructed on either ends of the station box. 2 EPB TBMs will be procured under this contract. The TBMs will do an initial north drive to Havelock station before docking, dismantling and reassembling for the second drives to Maxwell at the south. The alignment of the TSL tunnels to Havelock run directly beneath the existing EWL tunnels for a good 500 meters. A cross passage will be located here. Similar to contract T212 at Upper Thomson, this will be the first time excavation of a tunnel parallel and beneath and existing operational MRT tunnel is being executed here.

Tunnels to Maxwell will go beneath the existing footings of shophouses near Kreta Ayer

Update Progress
The site office has just been completed and is located behind the soon to be demolished Pearls Centre. Works are midway to surface the slab on the site ground. On areas with the completed slab, the bentonite plant and silos have been erected. Trench Cutters are also being assembled on the site.

T222 Site office at 102A Eu Tong Sen St

Pre-assembled trench cutters and erected bentonite silos