IOM3 HK - Technical Site Visit to Contract No: NL/2017/03 Tung Chung New Town Extension (TCNTE)
The Hong Kong branch successfully organized a technical visit to TCNTE on 27 April 2019 (Saturday) with 15 numbers of participants. We were welcomed by AECOM team - the Senior Resident Engineer, Chris Cheung, Resident Engineers, Giovanni Chang and Kelvin Kwan, and Assistant Resident Engineer, Jessie Tang. The visit began with an introductory presentation given by Miss Tang. She described in detail various aspects including project background, reclamation method, ground treatment, environmental and sustainable initiatives as well as public relations.
The TCNTE is the first new town extension project via reclamation since the completion of the last new town development projects by reclamation in Tseung Kwan O and Tung Chung in 2003. The TCNTE project is also one of the major initiatives under the Government’s multi-pronged approach to increase land supply in the medium to long-term. The Government plans to further develop the Tung Chung New Town into a comprehensively-planned new town to accommodate a larger population capacity with adequate local and regional community facilities.
The approximate 130 hectare reclamation is surrounded by a combination of eco-shoreline and vertical sea walls. The works include construction of drainage box culvert and Interim open rectangle channel. The participants had better understanding of the reclamation works, which adopted non-dredged reclamation technology methods for reclamation and construction of seawalls which avoided the requirement to remove the soft marine deposits that are present at the site. The method requiresground improvement including surcharging with prefabricated vertical drains, as well as Deep Cement Mixing (DCM). The construction sequence was explained in detail for example, starting with geotextile laying, then sand blanket placing, installation of vertical drain, then public fill placing.
Various environmental parameters were closely and systematically monitored during the site work i.e. air quality, noise, water quality and ecological aspects. Eco-shoreline is proposed to enhance biodiversity and promote water-friendly culture. It consists of rock armor seawall and mangrove shoreline. Mr. Chris Cheung said the species of mangrove will be carefully selected based on local site condition. The project also made specific effort on community liaison and maintained excellent public relations with nearby stakeholders.
The presentation was followed by a site visit, which required transport by marine vessel as the reclamation works was still ongoing. Participants had the opportunity to see various non-dredged reclamation technology methods in progress. The mechanism of forming DCM columns was explained and the DCM method has advantages of large strength and little adverse impact on environmental. Giovanni Chang and Kelvin Kwan explained that marine DCM barges were equipped with injection nozzle, augers, mixing shaft, A-shaped frame, binder silo, mixing plant and slurry pump. Seven (7) numbers of DCM barges were working in the area on the date of the visit. The site has some specific logistical constraint – it is next to Tung Chung buoyed channel, and there is limited headroom beneath an existing viaduct of TMCLK Link under which the DCM barges had to pass. This required a special arrangement such as dismantling the A-shaped frame before crossing. Sand blanket placing work was also ongoing with a number of sand carrier vessels on site. The worksite has been surrounded with silt curtain in order to prevent silt dispersion and maintain water quality.
We were impressed with AECOM’s effort to lead this visit and particularly appreciate their experience and knowledge sharing. Thank you to Mr. Chris Cheung, Mr. Giovanni Chang, Mr. Kelvin Kwan, and Miss. Jessie Tang. Last but not least, we would express our deep appreciation to CEDD for their approval for organizing the visit.
Souvenir presentation – From Left to Right: IOM3 (HK) Honorary Treasurer-Tim Leung; SRE-Chris Cheung; RE- Giovanni Chang; IOM3(HK) President-Kelvin Choi; ARE-Jessie Tang; and RE-Kelvin Kwan
Group Photo with DCM barge as background
Several DCM barges in action on sea
Presentation by Mr. Giovanni Chang