Issue 2 – APRIL 2020 Kim Chuan Depot Extension Keppel Station and Tunnels Prince Edward Road Station and Tunnels Circle Line 6 CLOSING THE LOOP BY 2025 Cantonment Station Cut-andCover Tunnels at Marina Bay Area Scan to find out more about the CCL6 contents CREDITS Project Director Mr Lim Kian Peng Deputy Directors Mr Sihan Sadikin Ms Juila Lim Page Director’s Message Mr. Lim Kian Peng Contributors LTA Project Teams for Feature on Traffic Diversion of Kim Chuan Depot extension Keppel Station and Tunnels (C882) Cantonment Station (C883) Prince Edward Road Station and Tunnels (C885) Commencement of Tunnelling Works between Keppel, Cantonment and Prince Edward Road Stations Kim Chuan Depot Extension (C821A) Cut-and-Cover Tunnels at Marina Bay Area (C886) LTA Community Partnership Managers Mr Benjamin Tan Ms Nurly Sudin Mr Kim Kian Meng Mr Md Ridwan Main Contractors China State Construction Engineering Corporation Limited (Singapore Branch) and Nishimatsu Construction Co. Ltd Joint Venture China State Construction Engineering Corporation Limited (Singapore Branch) China Railway Tunnel Group Co., Ltd (Singapore Branch) Koh Brothers Building and Civil Engineering Contractor (Pte) Ltd Woh Hup (Private) Limited 3 Naming of Tunnel Boring Machines 4 6 8 9 Human Interest Stories Engaging the Community Keeping Track Upcoming Activities In Touch 11 13 15 16 2 Project Director’s Note Dear Residents and Stakeholders Welcome to the 2nd issue of the Circle Line 6 (CCL6) Project Newsletter! I am delighted to update you on the progress and the upcoming construction activities for the five CCL6 civil contracts namely Keppel Station, Cantonment Station and Prince Edward Road Station, Cut and Cover Tunnels at Marina Bay Area, and Kim Chuan Depot Extension. The entire CCL6 is 4km long and when completed, it will serve as an accessible mode of transport for residents and stakeholders. The completed stations will close the loop for the Circle Line and conveniently connect you to the existing MRT network. Building an underground MRT system comes with many challenges. One major challenge is the proximity of the worksites to residential buildings. We have received feedback that the construction works have caused some environmental concerns such as noise and dust. Please be assured that we are listening and will work with our contractors to implement measures to minimise these inconveniences. I am pleased to report that the construction works are progressing well. Most of the diaphragm wall works, the traffic and utility diversions, and ground improvement works have completed. The excavation works for the construction of the stations and tunnels are currently in progress. I am extremely grateful for the support given by you over the past two years. I seek your continuous patience and understanding for the remaining construction works. Thank you and be blessed with all that makes you happy and healthy. LIM KIAN PENG Director (Rail Expansion) Civil Team 1 3 Cover Story Feature on Traffic Diversion of Kim Chuan Depot extension Temporary Traffic Diversions The existing Kim Chuan Depot (KCD) will be extended with the construction of a two-level underground Rail Depot and an above ground three-level Bus Depot on the adjacent 16 hectare land. The heavily utilised Hougang Avenue 3 and Kim Chuan Road which spans across the KCD Extension footprint must be diverted in phases to facilitate the extension of underground rail depot. To ensure a high level of safety for all road users, the carriageways were temporarily diverted onto steel structural traffic decks. These decks are supported by steel circular columns constructed with the foundation piles. A major challenge was the construction of the foundation piles within proximity to existing ‘live’ underground utilities. This was overcome with the conduct of extensive site investigation to positively identify the alignment of the utilities, the implementation of utility damage prevention measures and the close coordination with the various utility agencies before commencing the piling works. To safeguard public safety, rigorous safety inspections were carried out during the construction of the traffic decks along the existing ‘live’ carriageways. All temporary traffic diversions required for the next phase of the underground rail depot works have been successfully implemented in 2019. Reinstatement of Kim Chuan Road and Hougang Avenue 3 are scheduled to be carried out by 4Q 2020 and 1Q 2022 respectively. Diverted Kim Chuan Road Original Kim Chuan Road (Closed to Traffic) Overview of the original and the diverted Kim Chuan Road 4 Cover Story Temporary Traffic Diversions at Hougang Avenue 3 Former Hougang Ave 3 Former Hougang Ave 3 Towards Eunos Diverted Hougang Ave 3 (towards Hougang) Overview of Former Hougang Avenue 3 Diverted Hougang Ave 3 (Towards Eunos) Stage 2 Traffic Diversion - Overview of Diverted Hougang Avenue 3 (Towards Eunos) Stage 1 Traffic Diversion - Overview of Diverted Hougang Avenue 3 (Towards Hougang) Diverted Hougang Ave 3 (Towards Eunos) Final Traffic Diversion - Overview of Diverted Hougang Avenue 3 (Towards Eunos) 5 Cover Story COMMENCEMENT OF TUNNELLING WORKS BETWEEN KEPPEL, CANTONMENT AND PRINCE EDWARD ROAD STATIONS Cross-section of Tunnel Boring Machine Earth Pressure Balance Tunnel Boring Machine Earth Pressure Balance (EPB) Tunnel Boring Machines (TBM) are used to construct the MRT tunnels connecting Keppel, Cantonment and Prince Edward Road stations. The EPB helps to balance the earth and hydrostatic pressure from the surrounding ground throughout the tunneling works. The EPB TBM is made up of several large metal cylinders known as TBM shields. The rotating cutting wheel, commonly known as cutter head is equipped with cutting tools and is sited in front of the shield. During excavation, the set of hydraulic jacks behind the chamber will be extended against the tunnel wall to push the TBM 6 forward. At the same time, the cutterhead rotates to cut the soil and rock strata in front of the machine. The “cut” soil and rock strata will fall into the chamber through the openings at the cutterheads and will be used to balance the earth and hydrostatic pressure from the surrounding ground. Precast concrete segment linings will be built behind the TBM upon completion of each excavation cycle. Seven segments with one key segment are bolted together to form one complete ring of the bored tunnel wall. The excavated materials will be transported out from the chamber via screw conveyor and transported out of the tunnel using locomotives.