Thursday, February 7, 2019

Construction progress at T302

As the Land Transport Authority (LTA) recently announced the addition of Founders' Memorial station, it was mentioned that the construction of the new addition would begin in 2019. This statement was misleading as Founders' Memorial station was being partially constructed as an interim facility building as a future, unopened station on the line under contract T302. It was subsequently added that this would be done by converting a planned facility building into an operational station.

Details of contract T302.
Source: LTA

The contract calls for the construction of the station box with two launch shafts at either end. The southern launch shaft would facilitate construction of bored tunnels to the Gardens by the bay Marina East shaft constructed by contract T228's contractor on the Thomson Line section. The northern launch shaft would facilitate construction of bored tunnels to connect with the cut and cover tunnels along Tanjong Rhu Road. Let us take a look at some of the milestones achieved by the project contractor to date.

23 June 2018 - An overview of the T302 worksite.
Contract T302 has been in progress since 2016, with heavy works at the site in Gardens by the Bay East requiring the diversion of some of the footpaths in the gardens.  According to contractor China Railway First Group (CRFG), diaphragm walls for the station site were completed in October 2017.

Aerial view of T302 station construction site.
Source: China Railway First Group (CRFG)

Bored pile works underway.
Source: CRFG
The southern launch shaft was subsequently completed in February 2018 and followed by assembly of the first tunnel boring machine (TBM) in March 2018. Assembly took approximately 2 months and a launch ceremony was held for the commencement of boring for the southern tunnels by the machine, named TBM #1.

TBM cradle ready to support the machine during its initial drive.
Source: CRFG

A portion of the TBM shield being lowered down into the south launch shaft.
Source: CRFG
The completely assembled TBM1 on the Changi bound track ready for launch.
Source: CRFG

A launch ceremony was held for commencement of tunneling works for TBM1 on 9th May 2018.
Source: CRFG
The completed TBM lies on the cradle, ready for launch.
Source: CRFG
Following TBM#1's launch in May 2018, tunneling towards the reception shaft in the Gardens by the Bay East began. As the distance between the launch and reception shafts was not extremely long, preparations for the breakthrough of the TBM began around September 2018.

21 September 2018 - A view within the reception shaft. On the left are tunnel eyes being prepared for the breakthrough by the T302 team. On the right are completed tunnels by the T228 team, which run under the Marina reservoir.
Source: Sorrasak Marueang

21 September 2018 - Preparation of the tunnel eye in anticipation of the TBM breakthrough in the reception tunnel.
Source: Sorrasak Marueang
On 26 September 2018, TBM#2 on the Woodlands bound tunnel had achieved breakthrough at the reception shaft. As typical for any breakthrough event, some photos were taken to commemorate the completion of the tunnel drive.


Staff celebrating the completion of the two southern tunnel drives to the Gardens by the Bay Marina East reception shaft.
Source: CRFG
Photo taking with the commemorative banner.
Source: CRFG
View of TBM#2 after completing its drive.
Source: Sorrasak Marueang
Subsequently, on 9th October 2018, both TBM#1 on the Changi bound tunnel achieved breakthrough at the shaft. We've found a video of the breakthrough of TBM#1 as below, by Kumar Vr Sing Built.


By December 2018, the contractor had begun pumping in concrete into the tunnels for the first stage of the track bed. Once cured, the tunnels would have achieved basic structural completion and can be handed over to the trackworks contractor who would bring in the steel rails attached to concrete sleepers. A layer of rebar is placed over the first stage track bed and helps to provide a stable plane on which the tracks can sit. A further layer of concrete is poured to ensure that all components sit in place accordingly.

Concrete pumping in the tunnels underway for first stage of track bed.
Source: Sorrasak Marueang

Source: Sorrasak Marueang
In 2019, TBM assembly began in the northern shaft for the drives towards Tanjong Rhu station. The TBM shield was lifted in on January 15th and the cutterhead on January 16th. Once assembled, the TBM is likely to begin its drive around end-February or early-March.

15 January 2019 - Lowering of the TBM shield into the northern launch shaft.
Source: Sorrasak Marueang

Source: Sorrasak Marueang

16 January 2019 - Lower of the cutterhead into the launch shaft.
Source: Sorrasak Marueang

Source: Sorrasak Marueang
Both northern tunnel drives should be completed within 2019, inching the East Coast stretch of the line towards further milestones. Residents in the area up to Tanjong Rhu can expect soil monitoring activities to commence as the TBMs progress towards the boundary with contract T303. Soil improvement works near the contract boundary may be necessary to strengthen the ground in anticipation of the arrival of the TBMs as well.

No comments:

Post a Comment