Date, time & venue
Due to inadequate capacity of the existing drainage systems, Sham Shui Po, Cheung Sha Wan and Lai Chi Kok areas are susceptible to flooding during heavy rainstorms. The Lai Chi Kok Transfer Scheme is a drainage tunnel that will capture rainwater from the upper catchment in West Kowloon and discharge it into Victoria Harbour to alleviate flooding of the low lying, developed areas of Kowloon. The project comprises the construction of a drainage tunnel of about 3.7km in length and about 4.9m in diameter from Chak On Estate to Victoria Harbour near Stonecutters Island; six intakes and about 270m of connection adits; a stilling basin and an outfall structure; and slope stabilization works. The tunnels will be constructed by TBM and will pass through rock, mixed ground and soft ground strata. The connection adits will be constructed by blasting techniques. Depending on the ongoing site activities, attendees to the site visit may have a unique opportunity to get a close up view of the TBM operation.
09:15 – 09:25 Gathering & Register at Security Guard’s Hut
09:30 – 09:45 Safety Induction by Contractor Safety Officer
09:45 – 10:45 Presentation of the project by RSS of AECOM, Q & A
10:45 – 12:00 site tour and group photo
Meet at the conference room on G/F inside AECOM’s Supervising Officer’s Representative (SOR) Office at 39 King Lam Street (location as shown on map attached). Parking is not provided for site visit attendees. Latecomers will NOTbe entertained.
On 18 June 2011, the Civil Division and the AECOM jointly organized a technical visit to Lai Chi Kok Transfer Scheme.
To mitigate the flooding problem of Sham Shui Po, Cheung Sha Wan and Lai Chi Kok Districts, the government is constructing Lai Chi Kok Drainage Tunnel to collect the stormwater from the upstream of the original catchment area and directly discharge to Victoria Harbour. This project comprises the construction of a 4.9m diameter 1.2km long main tunnel, 4.9m diameter 2.5km long branch tunnel, 6 intake shafts, stilling basin, 2 main tunnel shafts, outfall and landscape work. The basic principle of this project is to intercept the stormwater of ruralupper catchment from major stream courses and underground pipes by 6 intakes. The stormwater collected in those intakes will be diverted through the drop shaft to adit and branch tunnel, and then transferred to the stilling basin and main tunnel. Finally, outfall to Victoria Harbour. Flow through the urbanized lower catchment will be much reduced by this scheme.
Firstly, the site supervision team gave us an excellent presentation on the project works to enable us to acquire knowledge about the TBM and drill-and-break tunnel excavation methods. In this project, Slurry Tunnel Boring Machine was the chosen plant for the tunnel excavation works because it is suitable for the geological condition of this project and the TBM can bore though both hard rock and mixed ground easily.
During the visit, the participants had the opportunities to visit the branch tunnel. As we walked through the branch tunnel, we saw the completed segmental tunnel lining clearly and there were 6 precast concrete segments forming a ring support of 4.9m diameter tunnel. The segments were well placed by the TBM and the waterproofing between segments is good. We can feel the engineers’ punctiliousness and earnest. We also visited one of the vertical shaft connection works within the branch tunnel and it was a great experience closely visualizing the drill-and-break excavation works within the tunnel.
After visiting the branch tunnel, the site supervision team brought us to the on-site slurry treatment plant. We had the opportunities to closely see the slurry treatment activities and it was an unforgettable experience to feel the enormous vibration of the treatment plant in operation mode.
Before calling to the end of the visit, we visited the launching shaft of the main tunnel. The excavation works of the main tunnel was still in progress and we had a glimpse of the general arrangement of the launching area.
Finally, we would like to sincerely thank the site supervision team for their kind arrangement in this visit. so that the participants could have more understanding on the tunnel excavation works of Lai Chi Kok Transfer Scheme.
Please visit photo album 20110618 Visit to Lai Chi Kok Transfer Scheme
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