Discover the transformative Tseung Kwan O–Lam Tin Tunnel, enhancing connectivity and reducing travel time.
The Tseung Kwan O-Lam Tin Tunnel (TKO-LTT) is a milestone infrastructure project featuring a dual two-lane carriageway that spans 3.8 km in length, including a 2.2 km main tunnel and a branch tunnel connecting to the Eastern Harbour Crossing. The tunnel has greatly alleviated traffic congestion and reduced journey times by 20 minutes during peak hours. It also creates an opportunity for waiving the toll of the TKO Tunnel.
AECOM was appointed to conduct the investigation study, design, and construction of TKO-LTT.
People-based engagement strategy that emphasized social and environmental sustainability
We alleviated public concerns by proposing a straight tunnel design without a toll plaza which reduced reclamation works by 75% and preserved 1.2 km of natural shoreline. Considering local residents and the integrity of the nearby Cha Kwo Ling Village, we designed the Lam Tin Interchange’s main carriageway to be constructed below ground level. This strategic placement, combined with a landscaped deck and noise barriers, significantly mitigates environmental and visual disturbances.
Our approach to water conservation was equally innovative where we adopted a hybrid reclamation method for the construction of the underpass Road P2. TKO-LTT was the first project to adopt a temporary steel cofferdam and a double water gate system for reclamation works in order to minimize sediment flow to the open sea.
Innovative engineering: Multi-level design and pioneering tunnel bifurcation
At the Lam Tin Interchange, the interchange comprises of multilevel superstructures to provide the designated routes that required well planned construction sequence and logistic in a compacted ex-quarry site.
A significant achievement was the tunnelling of a branch tunnel with tunnel bifurcation – the first time for a road tunnel in Hong Kong – using drill and blast method. It reduced excavation material, while excavated marine sediment has been treated and re-used for backfill. The 38 m excavation span at the turnout presented a major tunnelling challenge, as was ensuring fire safety for the branch tunnel. Yet, the Fire Services Installations Acceptance Inspection for the road tunnel was completed in only 6 weeks compared to 3-4 months normally.
Due to space constraints, ventilation of the branch tunnel had to rely on the Western Ventilation Building at the Lam Tin Interchange. A ventilation adit, built by connecting the main and branch tunnels close to the portals, was designed with a 45-degree inclination to reduce pressure loss – more efficient than the conventional approach and making the ventilation system more energy efficient.
First road tunnel with a ventilation building partly nestled in a cavern
TKO-LTT also pioneered the construction of a ventilation building in a cavern for a road tunnel. This allows for underground placement of the majority of fan and plant rooms, resulting in a smaller footprint and significantly reducing excavation and soil nail requirements at the steep terrain of the TKO portal. The smaller slope cutting area has also helped to preserve valuable green belt habitat.
Overcoming construction challenges, such as controlled blasting near MTR lines as close as 12 m and open blasting at higher ground overlooking the MTR ventilation building, state-of-the-art blast design and technology was used to control ground vibration and monitor the impact, while a mini roof-over system prevented flyrock.
Upon the gradual completion of new developments at Tseung Kwan O new town, the completion of TKO-LTT and Cross Bay Link have improved the transport network and facilitated the commuting public.
Awards and recognition for TKO-LTT
- HKIE Grand Award 2024 – Grand Prize (Infrastructure category)
- ACEHK Annual Awards 2023 – Annual Award
- HKIE Geotechnical Project Excellence Award 2023 – Merit Award
- NCE Tunnelling Awards 2020 – Environment and Sustainability Initiative of the Year