16.00 – 18.00 Vertical shaft construction site at Contract 923A, DTL 3

About Contract 923A, DTL 3

The Downtown Line Stage 3 (DTL3) is part of the Downtown Line MRT system. It is divided into 3 A/E (Architectural & Engineering) design packages: Package A, B & C. The Contract 923A is part of DTL3 Package C which comprises of 6 stations and estimated tunnel length of 16km. The six MRT stations are Expo Interchange (XPO), Upper Changi (UPC), Tampines East (TPE), Tampines Central (TPC), Tampines West (TPW) and Bedok Reservoir (BDR).

Contract 923A (C923A) comprises the construction and completion of a section of the twin bored tunnel from C925 Tampines East Station (TPE) to C923 Upper Changi Station (UPC), including eight (8) cross passages and a circular shaft at PIE (known as the PIE Shaft). The total length of the bored tunnel is approximately 2.4km for each bound’s drive. Eight (8) cross passages shall be constructed along the approximately 2.35km long twin bored tunnels; PIE Shaft towards Tampines East Station measures 1.5km and PIE shaft towards Upper Changi Station measures 0.87km. One (1) of the 8 cross passage is rectangular in shape and located within the PIE Shaft. The other seven (7) of the cross passages are oval in shape.

About the vertical shaft

The PIE Shaft is 28m in diameter (internal) and approximately 42m in depth, as shown on the Drawings. The shaft is constructed with 500mm thick of shotcrete concrete as temporary support. Downtown Line 3 projects are targeted to complete in 2017.

Shaft under construction
Image Courtesy: STEC, China

Learning from the site visit

The site visit, led by Yan Zhen, Engineering Manager – Tunnels, Shanghai Tunnel Engineering Company, the construction contractor for the TBM driven tunnels and the vertical shafts in this package, will provide a detailed description of:

• The construction methodology used for tunnels and vertical shafts
• Lining materials and methods
• Temporary support installation procedures

Site Visit led by:

Yan Zhen
Engineering Manager – Tunnels
SHANGHAI TUNNEL ENGINEERING CORPORATION

With over 20 years’ experience Yan Zhen has involved in major civil engineering projects in the region including metro rail and water tunnels. From July 2012, he is the Engineering Manager of Shanghai Tunnel Engineering (Singapore) Pte. Ltd and is in-charge of various tendering projects in Singapore, Hong Kong, Malaysia and Qatar. He also gives technical support to the various site operations. He also is the Senior Tunnel Manager for MRT Downtown Line Stage 2 C920 project.