Visit to Contract No. DC/2009/05 : HATS 2A - Construction of Interconnection Tunnel and Diaphragm Wall for Main Pumping Station at Stonecutters Island Sewage Treatment Works

Date, time & venue 
2012-04-21;9:00 am. – 12:00noon;Exit A1 of MTR Cheung Sha Wan Station (Please see attached map)

 

 

Gathering Point

Exit A1 of MTR Cheung Sha Wan Station (Please see the attached map by clicking the top right icon of file)

 

 

Highlight

This HATS2A project involves the construction of 3.9m diameter Sewage Tunnel (250 mlong) where the ground stabilization at TBM break through adopts the ground freezing method which is rarely applied in Hong Kong. The construction of 55m diameter base slab and the cofferdam in the form of diaphragm wall is also a great challenge to the project. The cofferdam for the future sewage pumping station is claimed to be the largest sewage pumping station in Asia. Ongoing construction activities include TBM driving, active ground freezing work, segmental lining installation and the construction work at Inlet Chamber.

 

Rundown

08:45 – 09:00  Gather at Exit A1 of MTR Cheung Sha Wan Station

09:00 – 09:15  Travel to HATS 2A site office (HKIE will provide transportation)

09:15 – 10:30  Introduction of the project + Q&A Session

10:30 – 10:45  Safety Briefing

10:45 – 11:55  Site tour and group photo

11:55 – 12:00  Distribution of CPD certificates

 

Safety Equipment

Participants must bring along their own safety helmets, safety reflective vest, safety shoes and a valid Green Card (or HKIE Corporate Membership Card) if available.

 

Registration and Enquiry

The event is free of charge. The number of participants open for HKIE Civil Division member is limited to 30 on a first-come first-served basis.

 

As of 3:30pm of 16 April 2012, the number of registration exceeds the capacity. On-line registration is closed.

 

Successful applicants will be informed on or before 17 April 2012. For enquiry, please contact Ir. Ian Chung / Ms. Terri Tong at Tel: 3922 9861 or Email: terri.tong@aecom.com

 

Remarks

If any successfully enrolled participant does not turn up on the date of site visit without good reasons, his/her right to enroll HKIE Civil Division site visits will be suspended for 3 months after the date of the captioned site visit.

Report

 

 

 

By Ir Alan Wong

 

The captioned visit organised by the CV Division was successfully held on 21 April 2012.

 

With the growing population and urban development of the city, the public started to concern more on the increasing amount of sewerage.  In this connection, the project “DC/2009/05 – HATS2A Construction of Interconnection Tunnel and Diaphragm Wall for Main Pumping Station at Stonecutter Island Sewage Treatment Works” was proposed to improve the water quality in Victoria Harbour by upgrading the preliminary treatment works, constructing a deep tunnel system to convey the untreated sewage from Hong Kong Island to Stonecutters Island Sewage Treatment Works and expanding the disinfection facilities.

 

This world-class sewage treatment works project comprises the construction of interconnection tunnel (3.9m internal diameter and 236m long) between the new influent pumping station and the pumping station inside Stonecutters Island Sewage Treatment Works; 1500mm thick diaphragm wall for the new influent pumping station and the associated chamber, excavation works and pilling works.

 

The design and site supervision works was undertaken by Ove Arup & Partners Hong Kong Ltd., whereas the construction works was awarded to China State –Shanghai Tunnel Joint Venture (CSSTJV).  The project commenced in late September 2009 and is expected to be completed in early 2012.

 

The visit began with an opening speech by Mr. W.L. Chan, representative of DSD, then followed by a brief presentation by Mr. Chris Leung, Mr. Gary Hong, Mr. Esmond Ng and Mr. Jeffrey Sin (the representatives from CSSTJV), which covered the overview of the project, scope of works, current progress of construction works, construction method and detailed construction sequence by tunnel bored machine (TBM) work, diaphragm wall and mini-piling works etc.  Some ground stabilization methods for TBM works including ground freezing were also introduced. 

 

A general safety briefing was given before starting the site tour.  The participants then visited the launching shaft area of the site to know more about the tunneling operation and diaphragm wall construction.  After visiting the launching shaft area, participants had an opportunity to visit the main Pumping Station and the inlet chamber.  Staff from CSSTJV introduced the construction method of cofferdam (55m diameter and 40m depth) and ground freezing equipment which is used to control crack of concrete during the tunnel construction.

 

An interactive question-and-answer session was held in the site visit, the participants did express their interest in the project.  At the same time, the site staff was also willing to share their experience and method for dealing with the difficulties during the construction.

 

We, on behalf of HKIE and the participants, would like to express our sincere thanks to Drainage Services Department and the Resident Site Staff team from Ove Arup & Partners Hong Kong Ltd. and China State –Shanghai Tunnel Joint Venture (CSSTJV) for their kind arrangement of this technical site visit.  Their impressive presentation and informative site tour provided an opportunity for us to broaden horizon, experience the tunnel work construction and improve our engineering knowledge.

 

 

 

Photos of the event

 

Please visit photo album 20120421 visiting HATS2A