LCQ11: Hong Kong-Zhuhai-Macao Bridge, Tuen Mun-Chek Lap Kok Link and Lantau Link
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Question:
It has been reported that the Hong Kong-Zhuhai-Macao Bridge (HZMB) is expected to be commissioned in the second quarter of this year. However, due to construction difficulties, the Tuen Mun-Chek Lap Kok Link (TM-CLKL) cannot be completed on schedule within this year in tandem with the commissioning of HZMB. The project is anticipated to be completed in 2020 at the earliest. The Lantau Link (comprising the Tsing Ma Bridge, the Ma Wan Viaduct and the Kap Shui Mun Bridge), which is currently the only vehicular access to the Lantau Island, will have to bear the additional vehicular flow brought by the commissioning of HZMB in the coming years, and traffic congestion is expected to deteriorate. It has also been reported that some of the steel cells of the steel cellular seawalls on the artificial island for HZMB Hong Kong Boundary Crossing Facilities have recently settled at an unusually quick pace, and that they may break the subsea tunnel of TM-CLKL underneath the steel cells in a worst-case scenario. In this connection, will the Government inform this Council:
(1) of the design capacity of the Tsing Ma Bridge;
(2) of the respective average hourly (i) traffic volumes and (ii) volume/capacity ratios of the Tsing Ma Bridge during the morning peak hours (eastbound), the morning peak hours (westbound), the evening peak hours (eastbound) and the evening peak hours (westbound) in the past three years (set out in a table);
(3) of the respective average hourly (i) traffic volumes and (ii) volume/capacity ratios of the Tsing Ma Bridge during the morning peak hours (eastbound), the morning peak hours (westbound), the evening peak hours (eastbound) and the evening peak hours (westbound) during the period between the commissioning of HZMB and that of TM-CLKL, as estimated by the Government (set out in a table); and
(4) whether it has assessed if the aforesaid settlement problem will further delay the completion of the TM-CLKL project; if so, of the details; if not, the reasons for that?
Reply:
President,
Regarding the commissioning date of the Hong Kong-Zhuhai-Macao Bridge (HZMB), the governments of the three places are currently striving to improve the clearance conditions of the boundary crossing facilities. The commissioning date of the HZMB will be reported to the Central authorities and will be announced once confirmed. In respect of the Tuen Mun-Chek Lap Kok Link (TM-CLKL) (see Enclosure 1 for its alignment), as stated in the press release issued by the Highways Department (HyD) in March 2017, the Southern Connection could be completed in the first half of 2019 at the earliest; while the Northern Connection in 2020 the earliest.
(1) and (2) The design capacities of the eastbound and westbound of the Tsing Ma Bridge are both about 4 700 vehicles per hour. The hourly traffic volumes and volume/capacity (v/c) ratios of the Tsing Ma Bridge (eastbound and westbound) during the morning and the evening peak hours on weekdays from 2014 to 2016, based on information from the Transport Department (TD), are set out respectively in Enclosure 2. As the traffic statistics of 2017 are still being consolidated by the TD, the traffic volumes and v/c ratios of the Tsing Ma Bridge of 2017 are not yet available.
(3) When the TM-CLKL was planned, it was already anticipated that its Northern Connection would only be completed two years after the commissioning of the HZMB. Based on the traffic forecast at that time, in the scenario without the TM-CLKL, the projected v/c ratios of the Lantau Link (both eastbound and westbound) during the morning peak hours in 2021 (see Enclosure 3) showed that the traffic conditions would be acceptable. Thus, we believe that the Lantau Link will not be congested during the period when the HZMB has been commissioned but the TM-CLKL has not yet opened. In any case, the Government will pay heed to the traffic condition upon the commissioning of the HZMB and take appropriate measures to ensure smooth traffic.
(4) It has been reported earlier that the steel cells at the artificial island for the HZMB Hong Kong Boundary Crossing Facilities (HKBCF) have settled unusually, and might even affect the subsea tunnel of the TM-CLKL underneath the steel cells. In response to such speculation, the HyD stated that the reclaimed land of the artificial island for the HZMB HKBCF had not shown any unusual settlement. The steel cells referred to in the media reports are temporary structures needed during the construction stage of the seawalls and reclamation. Normally, the settlement rate of steel cells is faster when the seawalls are being constructed and when the reclamation works are in progress. Upon the completion of the seawalls and the reclamation works, the settlement rate will slow down. According to the assessment by the consulting engineer for the HKBCF artificial island reclamation works, the settlement of both the permanent seawalls and reclaimed land meets the settlement standard, i.e. with residual settlement of 500 mm in 50 years after the completion of the reclamation works.
To tie in with the designed alignment of TM-CLKL subsea tunnel, in the course of devising the design for the HKBCF artificial island reclamation works, the consulting engineer adopted for the two steel cells (which are used for building the seawalls above the tunnel) an arrangement different from the other steel cells. Unlike the other 83 steel cells which rest their bottoms in the alluvium, these two steel cells have to rest their bottoms at the shallower marine mud, where stone columns have been installed. This arrangement is to maintain a safe distance of at least five metres away from the tunnel, so that the TM-CLKL Subsea Tunnel boring machines can enter the HKBCF artificial island from underneath the steel cells. Consulting engineer of the HKBCF artificial island reclamation works has anticipated that the settlement of these two steel cells will be larger than the remaining 83 steel cells during and after the reclamation works. The consulting engineer has also confirmed that the current settlement of the steel cells would not affect the structure and safety of the permanent seawall.
The consulting engineer for the HKBCF artificial island reclamation works has also conducted a detailed analysis on the settlement rate and condition of the two steel cells. Based on the findings of the analysis, the consulting engineer for the TM-CLKL is of the view that the settlement of the two steel cells will not affect the structure and safety of the subsea tunnel of the TM-CLKL. Also, the consulting engineer for the HKBCF artificial island reclamation works has further reviewed all steel cells, and no unusual settlement has been found for any of the steel cells.
As mentioned above, based on the present condition, the HyD anticipates that the TM-CLKL Northern Connection can be completed in 2020 at the earliest.
Ends/Wednesday, January 31, 2018
Issued at HKT 16:00
Issued at HKT 16:00
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