Leading global engineering and consulting firm Golder has been retained as geotechnical engineering advisor for the construction phase of the Hong Kong International Airport (HKIA) expansion project. The firm is working with Airport Authority Hong Kong (AA) to help identify and manage geotechnical risks and opportunities.
HKIA is one of the world’s busiest airports – carrying about 74 million passengers and around 5 million tonnes of cargo in 2019. However, with the existing airport reaching capacity, an expansion was needed to accommodate long term air traffic demand. After the completion of its US$18 billion Three-runway System (3RS) construction by 2024, HKIA will be able to serve 30 million additional passengers annually and handle increased cargo volume.
To enable a third runway and new passenger and cargo facilities, reclamation of 650 hectares is required to the north of the existing airport island. Between 2011 and 2015, Golder advised on the HKIA reclamation expansion from feasibility studies through to detailed design, helping to develop and optimise a geotechnical solution for the reclamation.
Since 2016, HKAA has engaged Golder directly to provide specialist independent geotechnical engineering advice for design and construction of all aspects of the airport extension. The new contract will now extend to completion of the airport project.
“We are pleased and proud to have been retained by our client as a trusted geotechnical advisor, so we can continue to develop and audit innovative engineering solutions to address the complex challenges of this large project,” said Dr Andy Pickles, Principal and Director at Golder in Hong Kong.
“A challenging aspect for the reclamation was the presence of contaminated subsea deposits of mud from previous reclamation projects around the Hong Kong area, which needed to be stiffened in place without affecting the marine ecology, rendering conventional dredging solutions unsuitable,” explained Pickles, who has been involved in the project since 2011.
A deep cement mixing (DCM) technique was applied across the reclamation area. Cement was injected and mixed through the contaminated mud to create cement clusters to support the seawall and the newly reclaimed land. Each cluster comprises four overlapping columns, approximately 1.2 m in diameter and between 20 and 40 m long. With approximately 250 000 cement clusters, this is the world’s largest DCM project.
“We were able to safely optimise the DCM works, saving vast volumes of cement, greatly improving the project’s sustainability, and also shortening the amount of drilling time required, reducing project costs.”
Golder will continue to interpret instrumentation and monitoring data, including from movement sensors at the seabed level and load cells that were buried in the ground before the reclamation.
“To identify any potential problems and to predict future performance of the reclamation, we are also trialing the use of interferometric synthetic aperture radar (InSAR) to monitor ground settlement, which is novel in such a recent reclamation and active construction environment,” added Pickles.
With the reclamation works now substantially complete, Golder is advising AAHK on geotechnical aspects of the expanded airport facilities, including the runway, taxiways and parking areas, new passenger terminal and tunnels for a new automated people mover and baggage handling system.
Operating in Asia for over 40 years, Golder brings a wealth of local and global knowledge and experience to clients in the mining, oil and gas, manufacturing, power and transportation sectors. Renowned for its award-winning geotechnical engineering expertise, the firm has advised on projects including Hong Kong’s MTR West Island Line, Tuen Mun-Chek Lap Kok Link, Lam Tin Tunnel and many others.
Learn more about Golder’s role in the Hong Kong International Airport expansion project.