3.1
This
section presents a summary of the adopted alignment and construction
methodology for the Project. The Project
consists of a 1.2 km long realignment branching out from the tunnel portal near Oi Man Estate (Portal 1A) to the new North
Ventilation Building, Plant Rooms and Emergency Access (NOV) in Hung Hom. The NOV will be constructed under the Shatin
to Central Link – Hung Hom to Admiralty Section [SCL (HUH – ADM)] project. Minor updates to the Project, such as
locations and structures, could occur during further design development and
construction, and these would be updated through the monthly EM&A
reporting.
3.2
As discussed in Section
2, the Cut and Cover Option was found to be the most appropriate option that can meet the Project
needs, benefit the public and be constructed with proven technology, with lower
costs and less programme implications. Underpinning construction method is the
preferred method for the construction of HUH.
Currently, a mixed fleet of Mid-Life Refurbishment (MLR) Train and SP1900 trains are
running on the East Rail Line (EAL). After the completion of SCL (HUH-ADM),
9-car SP1900 or equivalent with shorter train length will be adopted.
3.3
The
Project area, as illustrated in Figure
No. NEX2213/C/361/ENS/M50/502, is
land-based only with neither marine works nor use of sea-water cooling system. A preliminary construction programme of the
Project is provided in Appendix 3.1, with the primary
construction and operational phase elements displayed in Table 3.1 and 3.2
below.
Table 3.1 Construction Phase
Elements
|
Sections |
Key Construction Items |
|
Portal 1A (the most northern part of the
project boundary) to North of Hung Hom Station (HUH) |
• Construction
of a branch off track (with a trough and tunnel toward Chatham Road
Interchange) • Construction
Works Area above ground, e.g. Associated slope works at Oi Sen Path • Construction of Noise
Mitigation Measures at Portal 1A • Realignment of Cheong Wan Road |
|
North of HUH to Hung Hom NOV |
• Construction of the approach tunnel • Construction
of new platforms (at the existing HUH) • Construction of ventilation shafts at north and south of HUH • Construction
works areas above ground, eg. Cooling Tower • Operation
of one barging point with two loading ramps at Hung Hom Freight Pier (It will
be constructed by Kwun Tong Line Extension (KTE) before commencement of the
construction of the Project |
Table 3.2 Operational Phase Elements
|
Section |
Key Operational Items - Before Yr 2020 (Using
existing East Rail Line tracks and station) |
Key Operational Items - After Yr 2020 (after the
completion of the whole SCL) |
|
Portal 1A to north of HUH |
• Using
existing MLR/SP 1900 trains • Using
existing ballast tracks (above ground)
• Freight
train operations to cease • Infrequent
Intercity and maintenance locomotive movements, same as the prevailing
condition • Alignment of Ho Man Tin Siding slightly
revised |
• Using
new 9-car trains of SP 1900, or equivalent • Using
slab tracks at tunnel near • Using
new HUH platform • Freight
train operations
to cease • Infrequent
Intercity and maintenance locomotive movements, same as the prevailing
condition • Alignment of Ho Man Tin Siding
slightly revised |
|
North of HUH to Hung Hom NOV |
• Using existing MLR/SP
1900 trains • Using
existing ballast track (above ground) • Using
existing EAL platform • Freight
train operations
to cease • Infrequent
Intercity movement, same as the prevailing condition • Realigned
Cheong Wan Road • New
Exhaust/Intakes at HUH in operation (since Yr 2018) |
• Using new 9-car trains
of SP 1900, or equivalent • Using new slab tracks
(most are underground) • Using new
platform • Freight
train operations
to cease • Infrequent
Intercity movement, same as the prevailing condition • Realigned
Cheong Wan Road |
Preliminary Engineering Design
Considerations
3.4
The
information presented below is a summary available from the detailed design and
may be subject to further adjustment due to design evolvement.
3.5
The preferred alignment
has been adopted as a result of a thorough review of the engineering,
environmental and community impacts, as summarised in Section 2. The overall
alignment of the SCL is shown in Figure No. NEX2213/C/361/ENS/M50/501 with the generalised geological conditions and horizontal and vertical
alignments illustrated in Appendix 3.2.
Major Works Area/Site Requirements and Locations
3.6
In terms of the EIA context, works area/sites have been subdivided into
“major works area/site” and “other areas”. Major works area/site refers to the
integrated works item and works area/site that related to Designated Elements
under EIAO (e.g. for station and railway). In terms of other works area/sites,
they are further explained under Section 3.14. Major works areas for the
Project are illustrated in Figure no.
NEX2213/C/361/ENS/M50/502, and coloured in pink. In general, there are
three main areas, including the works areas for Chatham Road Interchange (CRI)
and associated tunnel, HUH, Hung Hom Freight Pier Barging Point.
Works Area for
CRI and Associated Tunnel
3.7
In order to minimise the potential disturbance and impact to the public
and environment, the major works areas are confined within the existing East
Rail Line boundary. The works area for the trough will be integrated into the
construction of the tunnel, which will employ a cut and cover construction
methodology as discussed in Section 2.
3.8
The tunnel works to the south of CRI would likely be constructed at a
similar time frame with the SCL (TAW-HUH) due to their interrelationship with
the SCL (TAW-HUH) tunnelling in respect to the proposed temporary diversion of
3.9
An existing Homantin siding (branching off from Portal 1A) will be
slightly modified. The three existing tracks will be reduced to one track with a
spur track approaching the Hong Kong Polytechnic University Phase 8 (HKPU Phase
8) area and the number of crossing will be reduced. The train
frequency and function of the sidings will remain unchanged.
Works Area at
HUH
3.10
New platforms would be constructed underneath the existing HUH. Some of
the construction works can be kept under the existing podium deck, and it is
expected that the environmental impacts could be much minimised. EAL can continue its
operation at the existing HUH during construction phase. The assessment would be based on underpinning
construction method being adopted.
3.11
Above ground works areas at HUH (outside podium footprint) will be
limited to those for the construction of the ventilation shafts, and cooling
tower. All these utility-supporting facilities will be typical small-scale
reinforced-concrete structures, and thus, adverse environmental impact would
not be anticipated.
Barging Point
at Hung Hom Freight Pier
3.12
The Hung Hom Freight Pier is currently employed for loading and
unloading of goods from freight terminal to the container barges. Owing to the
similarity with the existing loading and unloading operation, the Hung Hom
Freight Pier can be easily converted to barging
point for C&D
material. The Hung Hom Freight Pier having loading ramps, will be deployed to
serve this Project, SCL (TAW – HUH), SCL (HUH – ADM) and Kwun Tong Line
Extension (KTE).
3.13
It is anticipated that
the simplest form of loading ramps with an enclosed tipping
hall to be constructed, and a wheel washing facility would be
provided at the site exit to minimise construction dust and noise impact. Neither marine works nor modification to the
existing seawall is anticipated to be required for the Project.
Other Works Area/site within the SCL
Scheme/ Project Boundary
3.14
Apart from the major
works areas/sites, there are other areas/sites located within the SCL
scheme/project boundary at which minor activities/works for supporting
the construction of the Project may occur. In general, they are classified as
follows:
·
Other works
areas/sites – additional temporary works areas/sites would be required within
SCL scheme/project boundary for the provision of site office, storage of
materials, utilities, temporary traffic management scheme, temporary bridge, or
temporary pedestrian bridge and silo. Apart from the
landscape and visual impacts, these areas/sites would not cause any adverse
environmental impacts, and they are not included as part of the major works
area/site. (LVIA will be addressed comprehensively in Section 4 - LVIA
chapter). These works areas/sites will normally be used for typical
construction works that is not specifically bounded under EIAO legislation
(e.g. general utility works, construction or demolition of superstructure,
etc).
·
Off-site Area at
Mong Kok Freight Terminal – The office/store layout of the current freight
yards underneath MKK podium will be slightly modified. There will be neither
modification nor addition to the existing three rail tracks.
·
Tree Reception
Areas - All the trees affected by the construction of the Project would be
compensated within the Project boundary as far as possible. However, due to the availability of on-site
areas, some of the compensatory trees may need to be planted off-site. The locations of these off-site tree
reception areas are yet to be decided and subject to the tree felling
applications. Some possible sites that
may be considered include
·
Area linking
·
Area linking
3.15
Subject to actual site conditions and constraints, minor
preparatory works could also be required to be conducted in and around the project
boundary. However, these would only be
short-term without inducing major environmental implications to nearby
sensitive receivers. With the implementation of appropriate standard control
measures and good site practices for construction works, no adverse
environmental impact would be anticipated.
3.16
For ease of reference, Table 3.3
illustrates the above ground structure for the Project. The dimensions of these
structures are illustrated in Figure nos. NEX2213/C/361/ENS/M54/551 to 558.
Table 3.3 Permanent Above-ground
Structure
|
Sections |
Key Construction Items |
Abbreviations |
|
Portal 1A to North of HUH |
Noise
Mitigation Measures at Portal 1A |
- |
|
|
Cheong
Wan Road Viaduct |
- |
|
|
Homantin
Siding |
- |
|
North of HUH to Hung Hom NOV |
New
Hung Hom Station |
HUH |
|
|
North Side Ventilation Shafts |
NSVS |
|
|
South Side Ventilation Shafts |
SSVS |
|
North of HUH to Hung Hom NOV |
HUH Cooling Tower |
- |
|
Off-site Area |
MKK facilities |
- |
3.17
Major construction works include cut and cover works for
tunnel and surface works, construction of superstructures including ventilation
shafts, modification work to HUH podium structures as well as loading and
unloading at barging point.
Tunnel Construction
3.18
The tunnel structure is proposed to be
constructed by cut-and-cover (C&C) method in open area with a bottom-up
sequence whereas the section entering the HUH deck would be built by
underpinning method below the existing HUH podium. Some existing
superstructures located directly above the C&C tunnel would be demolished
before the construction of the tunnel.
3.19
The section of tunnel up to Chatham Road
Interchange will require prior reprovisioning of various infrastructure and
railway facilities directly affected by the alignment, and also the
underpinning of piers of the Hung Hom Bypass viaduct. The cofferdam
construction will use diaphragm walls, sheet pile walls, pipe pile walls or
secant piles subject to the contractor’s design. Significant underpinning works
are also required with respect to bridge piers of Hung Hom Bypass. The
foundation of the tunnels will be in the form of socketed H-piles, except where
floating structures may be used. Cut and cover tunneling through the Chatham
Road Interchange will require the implementation of a major temporary traffic
management scheme. It is proposed that this will generally involve the use of
sheet piled temporary retaining walls, except in the vicinity of existing
foundations where a stiffer support system will be used.
3.20
For the section south of the Hong Kong
Coliseum (HKC), the use of bored piles and pipe pile walls with in-situ tunnel
box construction inside the temporary cofferdam is proposed. Bored piles are also
used as the foundation systems for the tunnels. In addition, the existing CLP
Cable Tunnel and 1650mm diameter trunk sewer will need to be protected and
supported across the tunnel cofferdam.
Hung Hom Station (HUH) Construction
3.21
During the construction of the new HUH
platforms, to maintain existing traffic flow along
3.22
For the underpinning schemes at HUH,
underpinning by pipe pile wall and bottom-up method, column collar method and
in sequences are proposed. The majority of underpinning works relates to the
existing foundations and columns throughout the existing HUH footprint. A
significant proportion of the piles and pile caps are required to be demolished
to facilitate the station construction, and therefore extensive underpinning
works for the podium columns will be necessary.
3.23
In the area at the south end of the HUH,
the proposed Excavation and Lateral Support (ELS) system is subject to
contractor’s design. It could be
diaphragm wall, sheet pile walls, secant piles, pipe pile wall etc. In the central
part of the station, diaphragm walling is proposed due to insufficient space
for constructing both temporary wall and permanent station wall in respect of
horizontal alignment constraints relative to existing foundations. In the north
end of the station, a short section of pipe pile wall is proposed due to the
presence of the mid-level footbridge which imposes a significant headroom
constraint. After the underpinning works for the footbridge pier, the ground
level has to be lowered down for constructing diaphragm wall. In-situ end wall
is required adjacent to the proposed box culvert diversion in the north fan
area.
3.24
SCL (TAW-HUH) Modification works to the
existing HUH podium structure would be carried out to introduce openings for
new escalators, lifts and stairs and also to provide sufficient headroom for
the Mid-Level Walkway, E&M provisions and also works resulting from the
re-configuration and removal of existing columns of the Freight Terminal. The
modification works would only involve minor excavation work of which most are
carried out in an enclosed environment to minimize the disturbance to the
public and railway operations.
Other Works
3.25
Apart from the above construction works,
there are some supporting works, including demolition works, pile removal,
stormwater drain and culvert diversion and other associated works.
3.26
The existing storm water drainage network
serving (a) the HKC and the associated podium deck area (b) the existing HUH
complex (c) the existing PTI and Taxi drop-off area at the podium level, are
all connected to the existing culvert laid underground of the freight yard
area, via the storm water manhole network distributed throughout the area. It
is proposed to divert the section of the upstream culvert which passes through
the SCL footprint.
3.27
Ventilation shafts will be built at the
north and south of HUH podium edge for the operational tunnel and station
ventilation. The construction areas for these superstructures would be limited
and all structures are reinforced concrete in nature. The ventilation shafts
associated with the tunnel ventilation plant room is envisaged to be excavated
by cut-and-cover method. A sheet pile wall is proposed as the temporary
cofferdam wall.
3.28
Homantin Siding,
the former livestock sidings area, located at the south side of Chatham Road
Interchange would be reserved for railway reprovisioning works. Only minor
excavation works, e.g. realignment of the existing rail track and relocation of
the crossing would be carried out.
Barging Point at Hung Hom Freight Pier
3.29
The Hung Hom freight pier will be converted
into a temporary barging point with two loading ramps for spoil disposal. This
pier is to serve this Project, SCL (HUH-ADM), SCL (TAW–HUH) and KTE. The
establishment of this barging point would involve solely land-based works and
there would be no construction of marine structures. It is intended that the
considerable spoil quantities generated from the excavation works for the
station cofferdam, as well as the cut and cover works for the approach tunnels,
will be disposed of by barges. No stockpiles area would be provided for the
barging point, all excavated spoils would be delivered from the construction
sites by barge or truck every day. The disposal scheme will be that the spoil
is to be taken to sites within the Mainland for disposal.
3.30
The construction works would commence in
mid 2012 and the overall Project completion is anticipated to be in 2018.
3.31
Four groups of concurrent projects in the vicinity of the SCL have been
illustrated in Figure No.
NEX2213/C/361/ENS/M50/503 and identified as having genuine interfacing
issues. These are:
·
SCL (HUH - ADM);
·
SCL (TAW - HUH);
·
KTE; and
·
Improvement Works for Viaducts.
SCL (HUH-ADM) – Proponent as MTR
3.32
SCL (HUH–ADM) comprises of an approximately 6 km extension of the EAL
including a rail harbour crossing from Hung Hom across the harbour to Admiralty
on
SCL (TAW –
HUH) – Proponent as MTR
3.33
The SCL (TAW – HUH) is an approximately 11km long extension of the Ma On
Shan Line (MOL) from Tai Wai through new stations at Hin Keng (HIK), Diamond
Hill (DIH), Kai Tak (KTA), To Kwa Wan (TKW), Ma Tau Wai (MTW), Ho Man Tin (HOM)
and connects the West Rail Line at the HUH.
Most of these sections would be underground except for a section at Hin
Keng, and another section at Hung Hom. Open cut methods will be employed for the
construction of most of the station and ventilation building structures etc.
3.34
To support the SCL operation, three options for stabling sidings have
been developed, including using only the Diamond Hill CDA Site (namely DHS),
only the former Hung Hom Freight Yard (namely HHS) or a combination of both
sites. Subsequent investigation for the
preferred sites concluded that the option of combination of DHS and HHS was
found to be not preferred and was not pursued further. In this EIA Report, the
stabling sidings in DHS which is presented in the EIA Report of SCL (TAW-HUH)
is assumed and hence cumulative environmental impacts associated with the SCL
(TAW-HUH) with the DHS option have been assessed. The potential environmental
impacts associated with the HHS together with cumulative impacts from other
projects have been assessed and presented in another standalone EIA under the
EIA Study Brief No. ESB-233/2011. In that standalone EIA for SCL (HHS), the
potential cumulative environmental impacts from the Project and HHS, including
landscape and visual, construction dust, airborne noise, groundborne noise,
water quality, waste management and land contamination, have been
assessed/addressed. Adoption of the stabling sidings in DHS or HHS would be
subject to the findings of detailed engineering and EIA studies.
3.35
The SCL (TAW–HUH) will interchange with the KTE at HOM and the SCL (MKK
– HUH) and SCL (HUH – ADM) at HUH. The construction works is tentatively
scheduled to commence in 2012 and completed in 2018.
KTE – Proponent as MTR
3.36
This project consists of an approximately 3km extension of the existing
Kwun Tong Line from Yau Ma Tei (YMT) Station to a new railway station at
Whampoa and with an interchange with the SCL (TAW-HUH) at the proposed HOM. The
rail alignment is underground and the ventilation shafts and station entrances
are above ground-structures. The construction works are tentatively scheduled
to commence at early 2011 and be completed by 2015.
3.37
The project includes the construction of the running line from YMT through
proposed HOM to Whampoa Station (WHA) and the HOM and WHA along with their
associated structures. The construction of HOM is likely to interface and be
concurrent with the construction of this Project.
3.38
A rock crushing plant and one barging point with two loading ramps
located at Hung Hom Freight Pier are required to be constructed and operated
during the construction of KTE. The
crushed rock materials would be transported to the tipping halls of the barging
point by trucks and then unloaded to the barges. The crushed rock would be transported to the tipping
halls of the barging point by trucks and then unloaded to the barges. During the construction of SCL, the barging facilities
would be shared among this Project, SCL (HUH – ADM), SCL (TAW – HUH) and KTE. The
operation of the rock crushing plant is also likely to be interface and be
concurrent with the construction of SCL (MKK-HUH).
Improvement Works for Viaducts associated with
the Project
3.39
Improvement works for viaducts associated with Project include:
·
Upgrading of vehicular parapets for
·
Upgrading of vehicular parapets for Chatham Road Slip Road Bridge.
3.40
In terms of the upgrading of the
3.41
Upgrading of vehicular parapets for Chatham Road Slip Roads will be
added to both sides of the bridge deck. Thus additional widths will be added to
the sides while the kerb line is kept unchanged. The existing profile barrier
along the edge of the footpath will be also maintained. Details of the cladding
and finishing will be developed at the detailed design stage and the final
design will be submitted separately to the Advisory Committee on the Appearance
of Bridges and Associated Structures (ACABAS) for approval.
Central
3.42
The proposed Central Kowloon Route (CKR) comprises a dual 3-lane trunk
road across central
3.43
The proposed cable connects Ho Man Tin KCRC Substation and Tsim Sha Tsui
Substation. Initially, it runs
underneath the Chatham Road North Interchange and then along the
3.44
The proposed cable duct along the existing footpaths and carriageways
will be constructed mainly by open trenching method except for the proposed
no-dig cable duct crossing underneath Chatham Road North Interchange. The section potentially causing minor and
limited disturbance to the environment will be constructed by trenchless method
and no potential environmental impact will be anticipated. For other sections, to minimize any
disturbance to the surrounding environment, the construction works will be
conducted in phases. The construction works
will only involve minor and limited excavation works, and no adverse environmental
impact will be expected. Therefore, it
is anticipated that there will be no cumulative impact with the Project.
Summary of Concurrent Projects
3.45
The potential cumulative impacts of the identified concurrent projects
during the construction and operation of the Project are summarised in Table 3.4 below.
Table 3.4 Summary
of Concurrent Projects
|
Project |
Tentative Start |
Tentative Finish |
Construction Phase [1] Impact |
Operational Phase [1] Impact |
|
SCL
(HUH – ADM) |
2012 |
2020 |
Cumulative
dust and ground-borne noise impact at Hung Hom Station |
Not
anticipated (Not a worst-case) |
|
SCL
(TAW – HUH) |
2012 |
2018 |
Cumulative
dust and air-borne noise impact at Hung Hom Freight Pier, Hung Hom Station
and Chatham Road South Section |
Cumulative
ground-borne noise impact at Noise Sensitive Receiver (NSR) around Hung Hom
Station |
|
Kwun
Tong Line Extension |
2011 |
2015 |
Cumulative
dust and air-borne noise impact at Hung Hom Freight Pier and Chatham Road
South Section |
Not
anticipated (Good ventilation shaft design would be carried out by KTE to
avoid any cumulative visual impact) |
|
Central
|
Under
Review (Planned
to be commenced construction works in early 2015 |
Deep
underground – not anticipated |
Deep
underground – not anticipated |
|
|
Proposed
132kV Cable Circuits Connecting with Ho Man Tin KCRC Substation and Tsim Sha Tsui
Substation (Hung Hom Side) |
2012 |
2016 |
Trenchless
cable duct construction and limited open trenching cable duct construction –
negligible |
Not
anticipated |
Note: [1] Construction/Operation phase of the Project.
Continuous
Public Involvement
3.46
After the Executive
Council approved the further planning and preliminary design of SCL by the MTR
Corporation in March 2008, the Government and the MTR subsequently visited the
District Councils and consulted local communities on the Project. Extensive public consultation, including
roving exhibitions, public and professional forums, seminars, was conducted to further collect views from the public on
the new links.
3.47
The majority of the
public agreed that there is an overriding public need for the SCL and urged for
early completion of this infrastructure.
Having considered the views of the public, as well as all other
engineering and environmental factors, it is proposed that the Project is to be
implemented as described above.