CR111 - TBM Daphne

 

14 February 2025 - Group photo during the Geotechnical Society of Singapore's visit to contract
CR111's launch shaft with TBM Daphne visible behind.
Source: LinkedIn

Contract CR111 for the construction of Defu station and twin bored tunnels to Hougang station recently saw the launch of its first tunnel boring machine (TBM) last month. The TBM, named Daphne, will bore the westbound tunnel of the Cross Island Line (CRL), the mobile factory assembling tunnel segments along a route of approximately 1.5km.

14 February 2025 - Another group photo in front of TBM Daphne, which will be boring the
westbound tunnel towards Hougang station.
Source: LinkedIn

Tunnel construction is expected to be somewhat challenging, with the tunnel's route weaving through existing developments in Hougang town en route to the town's station. Preparatory works had been conducted such as soil improvement works where chemicals were injected into the ground along the proposed tunnel route to provide additional strength. Common difficulties encountered during tunneling include unpredictable soil composition despite advanced soil investigation, hidden pockets of soft or loose soil, undetected boulders or underground obstructions and undetected pockets of ground water. Despite these challenges, mitigation measures have been put in place to manage these risks which include advanced soil investigation works before the project design phase as well as during construction, visual surface monitoring for the early detection of soil settlement and the deployment of a comprehensive instrumentation network along the tunnel route to detect any unusual subsidence (soil settlement).

14 February 2025 - Participants within the open cut area of the launch shaft.
Source: LinkedIn

TBM assembly taking place within the launch shaft.
Image by KSL Tunneling

Welding of the TBM shield skins together.
Image by KSL Tunneling

TBM assembly taking place within the launch shaft.
Image by KSL Tunneling

TBM assembly - the corkscrew conveyor being lowered.
Image by KSL Tunneling

TBM assembly - the shield skins being aligned for welding together.
Image by KSL Tunneling

With the commencement of tunneling works here, yet another CRL1 contract has commenced tunnel construction. To date, the following contracts have begun using TBMs for such works:

1. Contract CR102 - Construction of tunnels between Changi East, CRL depot & Aviation Park station
2. Contract CR105 - Construction of large diameter single bored tunnel between Aviation Park & Loyang stations
3. Contract CR109 - Construction of Tampines North station and tunnels connecting to Pasir Ris station and Paya Lebar Air Base facility building
4. Contract CR110 - Construction of large diameter single bored tunnel between Paya Lebar Air Base facility building to Defu station
5. Contract CR111 - Construction of Defu station and tunnels to Hougang station
6. Contract CR112 - Construction of Hougang station and tunnels to Serangoon North station
7. Contract CR115 - Construction of Tavistock station and tunnels connecting to Ang Mo Kio & Serangoon North stations

A few other contracts remain to commence tunneling works:

1. Contract CR106 - Construction of Loyang station & tunnels connecting to Pasir Ris East station
2. Contract CR108 - Construction of Pasir Ris station & tunnels connecting to Pasir Ris East station
3. Contract CR116 - Construction of Ang Mo Kio station & tunnels connecting to Teck Ghee station
4. Contract CR117 - Construction of Bright Hill station & tunnels connecting to Teck Ghee station

We wish the contractors that have commenced tunnel construction a safe & expeditious completion of the works.

This post will also be available on Instagram & Facebook on 5 April 2025.