Stevens - Deep Cement Mixing

Ground improvement works are taking place around the Stevens Station for the past couple of weeks. Due to space constraints, only a single auger has been utilized in boring around the station box for the DCM works. Across the road, hoardings have just been erected along a boundary within the SCGS campus which has been designated and temporarily acquired as part of the construction of the new underpass and entrances. This site is expected to house the launch shaft for the CREG rectangular TBM which will bore the underpass beneath the canal, and dock at the escalator shaft.

The entrances and underpass have been promised to be completed 2 years ahead of the TEL station completion, in a bid to provide better connectivity between SCGS and the then-operational Downtown Line, in addition to an earlier reinstatement to the acquired SCGS site.

D-walling works continue at the Dalvey Launch Shaft.

Update Preview - Dalvey LS

T216 Stevens Station

Piling at Mount Pleasant (II)

Piling works have completed at the south launch shaft and the project team is preparing the site for excavation works. The priority now is to pile the north launch shaft - which will require a single slurry TBM to complete both bored tunnels toward Caldecott. The total tunnel excavation length is approximately 1.5km and would require about 2 years to complete.

Numerous handovers of the launch shafts would take place between the site's main contractor, adjacent T216 contractor as well as the trackwork contractor in the future. Delays are essential to be kept at minimum at every phase to prevent a snowball effect.

Aerial view of Mount Pleasant, T215

Caldecott Piles & Excavates (II)

Excavation works continue at the Caldecott site. 3 layers of struts have been constructed at its deepest point along the Thomson Cripple Siding. The shoring works at Caldecott are especially unique, where the contractor has bored down tubular concrete piles along the centreline of the earth retaining structure. The bore piles acts as columns supporting the horizontal struttings upon the commencement of excavation. With regards to material and method of construction, this is significantly different from the usual practice of an I-beam (aka king post) driven down to form the vertical component of the shoring structure.

Piling works continue closer to the north.

Caldecott Station, T213

Process of the conventional shoring works elaborated in this animation by Hirose (Singapore)

Upper Thomson Diverts

The first traffic diversion at the site of the Upper Thomson Station was implemented in February. The realignment of both carriageways to the south makes way for the initial earth retaining structural works on the north face of the station box, which should commence by next month.

At the entrance opposite Thomson Plaza, sheet piling works were carried out throughout the past month as well. The primary earth retaining structure for the entrance is now being d-walled. Silos have also been erected further up Bright Hill Drive. Piling works are now being done at the entrance of the former Thomson post office.

This post consists of the update for both the Upper Thomson Station and Upper Thomson Launch Shaft.

Update preview - Upper Thomson Launch Shaft

March 20 - Upper Thomson Station

Piling at Bright Hill (II)

Bore pile works continue at the north cut and cover tunnel, with an emphasis on the north launch shaft. The linear formality of the Bauers shows the north face of the shaft being piled at the moment. The north launch shaft should commence excavation by the third quarter. Several drain diversions are also taking place around the junction of Sin Ming Walk/Avenue and the south cut and cover tunnel site.

North Cut & Cover Tunnel

Piling at Mayflower (III)

SBP works have been on going for about 3 quarters now. A 3rd traffic diversion should take place around the middle of the year. 

Panorama of Mayflower Station, T210

Lentor & 5XO D-walls

D-walling works continue at the Lentor Station. Sheet piling for the subway leading to the Calrose Entrance has completed and shoring works are underway to construct the first layer of struts. Photos in this update were taken on March 14.

Shoring works for the underpass to Calrose across YCK road. The road will be diverted above this structure once a decking is made

Tagore Piles & Excavates (II)

The south launch shaft, together with a short portion of the adjacent cut and cover tunnel has been successfully excavated to the formation level (approx RL 99.000m). 4 layers of struttings have been constructed to support the 20m deep earth retaining structure. In addition, a pre-assembled gantry crane has been delivered and presently lies next to the shaft. The Slurry Treatment Plant (STP) has been assembled on site.

Inaugural bored tunnelling works for the Thomson Line look set to commence at the Tagore site around the middle of this year. 2 NFM Technologies TBMs will be launched from this shaft and driven 1.1km southwards to a retrieval shaft at the Lentor station. Upon breakthrough of the first tunnel, the first machine will be retrieved and re-assembled back at Tagore for a second drive towards Springleaf. 

Sites for the ground improvement works above the 3 cross passages (CP8D, CP9 & CP10) between Tagore and Lentor is evident from the aerial shots. Secant bored pile works continue around the north launch shaft and C&C tunnel.

Tagore Cut and Cover, T208

T208, Mix ground conditions along the tunnel route that the TBMs will interface (Cr: Noma)

Springleaf Diverts

The first traffic diversion for the Springleaf site was implemented at the end of January earlier this year. The Sembawang-bound carriageway of Upper Thomson Road now skirts away from the shophouses, segregating the worksite into two. As the station box sits beneath the entire span of the original road, a second phase of traffic diversion to realign the Thomson-bound carriageway has been planned and expected to be implemented in the later part of this year. 

D-walling works proceed around the station box.

Aerial view of T208, Springleaf Station

The bus stops around the site have all been included with a temporary shelter despite the permanent shelter constructed but hoarded off

Piling at Facility Building

2 piling machines are currently executing bore pile works at the site of the RTS Facility Building. Further north at the escape shaft, the circular earth retaining structure of the shaft seems to have completed and a mini gantry crane has been assembled. Due to the proximity of the escape shaft within the approach of runway 04 at Sembawang Airbase, the shallow gantry crane will facilitate lifting works at the shaft opening in place of a traditional mobile crane.

Shimz's site office for T207 at the north end of the Springleaf site overlooking the future launch shaft that will be handed over to them

Piling at RTS Facility Building

T206 Piles and Excavates (II)

We are pleased to share that the T206 project has achieved a half-million accident free man-hours at the beginning of this year. We review the intensive work that have been accomplished thus far.

One of the significant milestone achieved includes the deep excavation of Launch Shaft 2, and completion of the circular earth retaining structure for Launch Shaft 1. The LS2 which is 30m deep, have been dug to a depth of about 20m so far and seem to have encountered rock. LS1, which will launch out the reception tunnels, has a shallower formation level.

A treatment plant is under construction between the 2 shafts. Excavation of the shafts would have completed by our next update. We can expect the gantry cranes to be assembled and TBMs delivered to the site by then. Towards the south, piling works continue at the Sembawang Airbase C&C.

Progress of SBAB and Mandai Depot

Launch Shaft 1 (left) and Launch Shaft 2 (right)

Woodlands South D-walls (II)

D-walling works continue at the Woodlands South site. 2 piling machines and an additional crawler crane has been added to aid in the construction works from the previous update. We expect expect another quarters of D-walling works to proceed before Traffic Diversion 3 (TD3) gets implemented which involves a final realignment of Avenue 1 that will last through the remaining duration of the project.

Aerial view of T205, Woodlands South

Piling at Woodlands (III)

Piling works continue around the Woodlands site. Utility diversions are still on going around the junction of Ave 2/5, at which the first traffic diversion is expected to be implemented after the next quarter for the construction of the crossover tunnel box. Progress on the temporary Woodlands Regional Bus Interchange under T2211 is included in this update.

View from Causeway Point

Piling at Woodlands North

We begin another quarter's update on the progress of the Thomson Line construction at Woodlands North. A long auger drilling machine has arrived onto the site and positioned near the launch shaft. Beside it, several pile casings and rebar for the bored pile lay on the site floor. A desander plant seems to be in the process of being set up as well. At the launch shaft itself, piling has commenced with a concrete bored pile guide constructed to aid the drilling process. Earthworks are still being carried out at the crossover tunnel and station box.

Aerial view of Republic Polytechnic and the Straits of Johor bounding the Woodlands North site 

Drilling machine, pile casings and rebar beside the U/C desander plant next to the launch shaft