13. CONSTRUCTION METHODS, PROGRAMME AND USAGE OF NEW TECHNOLOGIES

13.1 Section 3.1 (xv) of the Particular Scope of the EIA Brief requires an assessment of: the details of the construction programme, the construction methodologies and an assessment of the extent to which the technologies to be employed are proven technologies.

13.2 The permanent work to construct the Spur Line can be summarised as the construction of the following major elements:

(i) East Rail diversion,

(ii) Diversion of the Dong Jiang watermains,

(iii) The ramps down to the cut and cover sections of tunnel,

(iv) The cut and cover sections of the tunnel,

(v) The bored tunnel,

(vi) The launching shaft, retrieval shafts, Kwu Tung station box, EAP structures, and ventilation buildings,

(vii) The ramp up to the viaduct,

(viii) The viaduct,

(ix) Lok Ma Chau station vehicular access

(x) Lok Ma Chau station,

(xi) The enhancement of the fishponds at Lok Ma Chau,

(xii) The construction of the footbridge crossing the Shenzhen River.

13.3 Associated with the permanent works are a number of significant temporary works:

(i) The jetties in the Shenzhen river for unloading materials,

(ii) Access roads,

(iii) Contractors compounds.

13.4 A summary project programme for the whole of the Spur Line is attached as Appendix A13.1

13.5 Each of the above major features are broken down into their constituent elements in the Table 13.1 below. The construction methods, programme durations, and commentary on the extent to which proven technology is adopted are shown. The programme durations shown below are for concurrent activities in many cases. The technologies to be used in construction have been discussed in detail in Section 2 - Description of the Works; and in other individual sections such as Chapter 3 – Hydrology, in respect of the usage of the Earth Pressure Balance technology in the tunnel boring work.

Table 13.1

Construction Methods, Programme and Degree to Which the Technology is Proven

Ref.	Feature/element	Method	Prog. Duration	Previous use
1a	Diversion of East Rail – temporary	Construct new formation for ballasted track.	2.5 years	Pak Shek Kok realignment
1a.1	Removal of planters in San Wan Road	Tree transplanting, tree felling, excavation.	6 months	Commonplace
1a.2	Construction of a new 2.4m diameter sewer	Diversion and reconnection of existing drainage by cut and cover techniques.	6 months	Commonplace
		Drive sheet piles and excavate by machine for the sewer and manholes.	6 months	Commonplace
		Construction of new in-situ reinforced concrete catchpits.	3 weeks each in phase with the excavation	Commonplace
		Lay granular bedding and precast pipes, backfill and compact.	3 months	Commonplace
1a.3	Prepare the trackbed formation	Breakout the road surface by machine. Excavate 600mm soil by machine and replace with granular fill, compacted. Lay track ballast to underside of sleeper, imported by road.	2 months	Commonplace techniques
1a.4	Installation of railway systems	Lay the sleepers – import by road and use mobile crane. Offload rails from a train and lift onto sleepers by mobile crane. Fill between sleepers with ballast, imported by road.	2 months	Commonplace methods
		Erect over headline mast by excavating for the base by machine and casting concrete around the prefabricated steel mast.	3 days each.	Commonplace methods
		Lay precast concrete troughs for control and communications signals by importing by road and laying by hand.	1 month	Commonplace methods
		Construct protective barrier by excavating for the base by machine and casting concrete around the prefabricated steel sections.	2 months	Commonplace methods
1a.5	Construct impact protection to Po Shek Wu Road Bridge	Construct 900 mm diameter reinforced concrete bored piles by piling rig using fluid to maintain stability.	1 month	Commonplace methods
		Excavate by machine using sheet piles to expose the pile heads. Construct in-situ reinforced concrete pilecap and upstand.	1 month	Commonplace methods
1b.	Final diversion of East Rail	Construct new formation for ballasted track and connect to existing operating East Rail without disruption to service.	1 year	Pak Shek Kok realignment with identical o’night placement and commissioning of turnouts.
1b.1	Formation works	Place granular fill to formation, imported by truck and spread and compacted.	2 months	Commonplace methods
		Import ballast by truck and lay to underside of sleeper.	1 month	Commonplace methods
1b.2	Railway Systems Installation	Lay the sleepers – import by road and use mobile crane. Offload rails from a train and lift onto sleepers by mobile crane. Fill between sleepers with ballast, imported by road.	2 months	Commonplace methods
		Erect over headline mast by excavating for the base by machine and casting concrete around the prefabricated steel mast.	3 days each.	Commonplace methods
		Lay precast concrete troughs for control and communications signals by importing by road and laying by hand.	1 month	Commonplace methods
1b.3	Remove temporary track	Cut rails and load onto a train by mobile crane. Excavate ballast by machine and load onto trucks for disposal.	1 month	Commonplace methods
		Construct road side gullies and connect to the storm drains. Install planter irrigation pipes.	1 month	Commonplace methods
		Lay road pavement – import materials by truck and roll to compact.	2 weeks	Commonplace methods
		Reconstruct planter in reinforced concrete, cast in-situ, with stone facing. Complete irrigation installation.	2 months	Commonplace methods
2	Diversion of the Dong Jiang watermains	Earthworks, foundations and new pipework to create a diversion of the mains.	18 months	Commonplace thrustblock and mainlaying methods
2.1	Earthworks	Excavate by machine. Load to trucks for disposal.	2 months	Commonplace methods
2.2	Construct thrust blocks	Bore minipiles and grout.	1 day for each pile, working progressively with the diversions	Commonplace methods
		Excavate to expose the heads of the minipiles and cast reinforced concrete thrust block.	1 week for each phase, working progressively with the diversions	Fan Kam Rd diversion of 1.2m diam main.
2.3	Lay pipes	Install minipile foundations, and cast a pipe support around the head in reinforced concrete.	2 weeks for each support	Commonplace methods
		Import new pipes by truck. String out on the new supports as far as possible using a mobile crane, and joint by welding.	1 month for each main	Commonplace methods
2.4	Tie-in to existing mains	Cut a section from the existing pipe and bring prefabricated joint section to site by truck. Weld joints.	1 month for each main	Commonplace methods
		Remove existing mains by flame cutting or unbolting as appropriate, load to a truck by mobile crane and dispose off site.	1 week for each main	Commonplace methods
3	Ramps down to the cut and cover sections	Reinforced concrete structures.	6 months for each ramp	Commonplace methods
3.1	Ramp walls	Install contiguous bored piles, 1m diameter, in reinforced concrete, using fluid for excavation support.	4 months	Commonplace methods
3.2	Base slab	Excavate soil by machine and remove by truck. Cast the reinforced concrete base slab.	2 months	Commonplace methods
3.3	Adjacent drainage channels	Excavate by machine open cut for the channel and dispose material off site. Arrange so that temporary drainage is always available – see DIA for details agreed with DSD.	2 weeks	Commonplace methods
		Cast channel walls and base in reinforced concrete.	3 months	Commonplace methods
		Backfill and compact fill imported by truck.	2 weeks	Commonplace methods
4	Cut and cover sections of tunnel	Diaphragm wall with reinforced concrete slabs.	12 months	Commonplace methods
4.1	Diaphragm wall construction	Install reinforced concrete lead trench.	1 month	Standard for all diaphragm walling jobs
		Set up plant for slurry stabilisation, including materials silos, settlement lagoons and pumps and pipes for circulation of slurry.	3 months	Ditto, but tunnel contractor will continue to use this plant for tunnelling. DB320 is most recent combined example.
		Mobilise rigs and excavate 800mm thick wall. Dispose of material off site by truck. Excavate every fourth or fifth panel approximately 1.8m in length.	2 days for each panel	Standard procedures
		Install reinforcement cage by crane and pour concrete into the panel.	2 days for each panel	Standard procedures
4.2	Roof and floor slab	Excavate between walls by machine and remove materials by truck.	3 months	Standard procedures
		Cast the slabs in reinforced concrete.	3 months	Commonplace
		Backfill on top of the roof slab with granular fill imported by truck, and compact.	1 month	Commonplace, eg all service reservoirs
4.3	Adjacent drainage channels	Excavate by machine open cut for the channel and dispose material off site. Arrange so that temporary drainage is always available – see DIA for details agreed with DSD.	2 weeks	Commonplace methods
		Cast channel walls and base in reinforced concrete.	3 months	Commonplace methods
		Backfill and compact fill imported by truck.	2 weeks	Commonplace methods
5.	The bored tunnel	Two no. bores by Earth Pressure Balance boring machine. All items are placed or removed from the launching shaft by a purpose installed gantry crane.	11 months for each bore + 3 months transit	KCRC Contrct DB320. Highly successful and no public complaint
5.1	Boring through soil	Using earth pressure balance mode, excavate soil under pressure in the head and remove from the bore. Allow to settle and treat supernatant to neutralise pH, remove oils and coagulate fines for complete removal of solids. Remove solids by truck for disposal.	300m/month	KCRC DB320 Contract. Very successful.
		Import precast segments by truck and place in the bore immediately behind the face shield. Grout annulus with cementitious mix, batched and mixed within the tunnel from materials brought to site by truck.	300m/month	DB320 Contract Standard tunneling procedures and completed tunnel is waterproof.
5a.2	Construct cross passages outside Long Valley	Establish rig on the ground and bore a 150mm diameter shaft to the cross passage level. Mix grout from materials brought to site by truck and inject into the ground on a grid basis, moving the rig for adequate coverage.	2 weeks/cross passage	Common construction technique
		Excavate by hand or small machine from inside the tunnel. Place the lining by spraying concrete, by mixing the materials inside the tunnel, brought to site by truck.	3 weeks/cross passage	Common construction technique
5b.2	Construct cross passages under Long Valley	Drill horizontally from within the tunnel to introduce cold fluid to freeze the ground.	3 weeks/cross passage	Regular Construction technique adopted where conditions dictate
		Excavate by hand or small machine from inside the tunnel. Place the lining by spraying concrete, by mixing the materials inside the tunnel, brought to site by truck.	3 weeks/cross passage	Common construction technique
5.3	Installation of the TBM	Face shield and the following train are brought to site on a series of trucks and lowered into the launching shaft for re-assembly.	3 months total	DB320 times two drives
5.4	Relocation of the TBM for the second bore	Face shield is lifted out in pieces from the retrieval shaft and transported back to the launching shaft on a series of trucks. The train goes back through the tunnel.	3 months	DB320 times two drives
5.5	Removal of the TBM	The face shield and supporting train are taken from the retrieval shaft in pieces and removed from the site on a series of trucks.	1 month	DB320 times two drives
5.6	Installation of railway systems	The track is LVT, which is a combination of reinforced concrete cast in-situ brought to the site by truck, and precast items. The rails are brought to site in long lengths by train, transported along the tunnel and welded in-situ.	8 months	DB320 and Airport Railway
		Overhead line supports are brought to the site by truck and fixed in place in the tunnel.	4 months	All existing KCRC East Rail Tunnels and DB320
		Cabling is laid out by large drums brought to the site by truck, running along the rails to install.	4 months	DB320
6.	The launching shafts, retrieval shafts, EAP shafts, Kwu Tung Station Box, and vent buildings	Diaphragm wall construction below ground, internal structure is reinforced concrete, above ground structures are reinforced concrete.	18months for each structure, but before tunnel boring is carried out at that location.	Common construction technique
6.1	Diaphragm wall construction	Install reinforced concrete lead trench.	1 month	Common construction technique
		Set up plant for slurry stabilisation, including materials silos, settlement lagoons and pumps and pipes for circulation of slurry.	3 months	Common construction technique
		Mobilise rigs and excavate 800mm thick wall. Dispose of material off site by truck. Excavate alternate panels approximately 1.8m in length.	2 days for each panel	Common construction technique
		Install reinforcement cage by crane and pour concrete into the panel.	2 days for each panel	Common construction technique
6.2	Internal slabs, walls and superstructure	Cast in reinforced concrete brought to site by truck, materials placed by mobile crane and skip.	12 months for each structure	Common construction technique
7	Ramp up to the viaduct	A piled structure with a reinforced concrete superstructure.	6 months	Common construction technique
7.1	Bored Piles	Install prebored H piles, with material excavated using a down-the-hole hammer. Materials for grouting to be brought to site for batching and mixing on site.	4 days/pile	Common construction technique
7.2	Superstructure	Cast in reinforced concrete brought to site by truck, materials placed by mobile crane and skip.	3 months	Common construction technique
7.3	Parapet	Concrete precast off site, brought to site by truck, lifted and placed by mobile crane, fixed into place by casting a stitch of reinforced concrete.	3 days for each panel, 1 month total	Common construction technique
7.4	Adjacent drainage channels	Excavate by machine open cut for the channel and dispose material off site. Arrange so that temporary drainage is always available – see DIA for details agreed with DSD.	2 weeks	Commonplace methods
		Cast channel walls and base in reinforced concrete.	3 months	Commonplace methods
		Backfill and compact fill imported by truck.	2 weeks	Commonplace methods
7.5	Installation of railway systems	The track is LVT, which is a combination of reinforced concrete cast in-situ brought to the site by truck, and precast items. The rails are brought to site in long lengths by train, transported along the tunnel and welded in-situ.	2 months	Common construction technique
		Overhead line supports are brought to the site by truck and fixed in place in the tunnel.	2 weeks	Common construction technique
		Cabling is laid out by large drums brought to the site by truck, running along the rails to install.	Cables laid with the rest of the alignment.	Common construction technique
8	Viaduct	A simply supported twin-cell precast prestressed concrete deck erected on falsework, supported by reinforced concrete piers and bored piled foundations.	18 months	Common construction technique Most of West Rail
8.1	Foundations	Install bored piles, 1.8m diameter, in reinforced concrete brought to site by truck and placed by crane and skip, using fluid for excavation support.	6 days for each pile	Common construction technique for last 30 years
		Open cut excavation to expose the pileheads, cast the pilecap in reinforced concrete brought to site by truck and placed by crane and skip.	7 days; 1 month for each foundation	Common construction technique
8.2	Pier	A single stem in reinforced concrete brought to site by truck and placed by crane and skip, using purpose designed steel formwork.	20 days for three pours	Common construction technique
8.3	Deck	Erect purpose designed falsework on the pilecaps at the end of each span using a mobile crane. Transport the falsework by truck.	3 days	Common construction technique
		Bring one cell precast concrete segments to site by truck and erect onto the falsework using a mobile crane. Stress together stage one.	1 day/span	Common construction technique
		Lower onto temporary bearings and repeat for the second cells for the span.	1 day/span	Common construction technique
		Cast the end diaphragms in reinforced concrete brought to site by truck, placed by crane and skip, and transfer load to the permanent bearings.	2 days/span	Common construction technique
		Grout the ducts for the tensioning strands by lifting materials onto the deck by crane, mixing and pumping materials on the deck.	0.5 days/ span	Common construction technique
		Place the parapets which are concrete precast off site, brought to site by truck, lifted and placed by mobile crane, fixed into place by casting a stitch of reinforced concrete.	3 days/span	Common construction technique
		Carry out stage 2 of the prestressing.	0.5 day	Common construction technique
		Remove the falsework using a crane, transport by truck and re-erect further on.	3 days	Common construction technique
8.4	Installation of railway systems	The track is LVT, which is a combination of reinforced concrete cast in-situ brought to the site by truck, and precast items. The rails are brought to site in long lengths by train, transported along the tunnel and welded in-situ.	2 months	Common construction technique
		Overhead line supports are brought to the site by truck and fixed in place in the tunnel.	2 weeks	Common construction technique
		Cabling is laid out by large drums brought to the site by truck, running along the rails to install.	Cables laid with the rest of the alignment.	Common construction technique
9	Lok Ma Chau Station Vehicular Access	Comprises a widening of the existing road and a realignment where it passes over the Spur Line.	3 years 4 months	Common construction technique
9.1	Formation works	Tree transplanting and felling.	6 months	Common construction technique
		Excavation of soft materials near the ground surface by machine, disposed off site by truck.	8 months	Common construction technique
		Deposition of granular materials brought to site by truck, and compacted by vibrating roller.	2 months	Common construction technique
		Installation of precast kerbs, road gullies and drainpipes by excavator brought to ite by truck, backfilled by granular materials and compacted.	2 months	Common construction technique
		Laying and rolling pavement materials brought to site by truck.	1 month	Common construction technique
10	Lok Ma Chau Station	Ground formation works by filling ponds, followed by piling and superstructure works.	3 years 9 months	Common construction techniques. See LMC Boundar Crossing
10.1	Formation works	The tops of the bunds forming the ponds in the station footprint are lowered by excavator, and the material placed in the area to be made a marshland. Geogrid and Wick drains, surcharge.	1 month	Common construction technique. See LMC Boundary Crossing
		Diversion of an existing watercourse by placing fill by machine, compacting it and forming the channel in grasscrete (precast conrete). Construction of a weir in reinforced concrete and excavation by machine for additional pipes to upgrade the existing outfall.	3 months	Common construction technique. See LMC Boundary crossing
		Sand fill is brought to the site by barge and placed in the ponds by a conveyor, displacing the remaining water in the ponds to neighbouring ponds.	6 months	Common construction technique. See Tin Shui Wai and River Trade Terminal
		Excavate trenches by machine using trench sheets for support, and place drain pipes.	4 months	Common construction technique
10.2	Piling	Install bored piles, 2.1m diameter, in reinforced concrete brought to site by barge and placed by crane and skip, using fluid for excavation support.	6 days for each pile	Common construction technique. See NTCR and LMC Boundary crossing
		Open cut excavation to expose the pileheads, cast the pilecap in reinforced concrete brought to site by barge and placed by crane and skip.	7 days; 6 months for foundation works	Common construction technique
10.3	Superstructure	Reinforced concrete brought to site by barge is placed using a crane and skip. Other materials such as cladding will be brought to site by barge and erected using a crane.	18 months	Common construction technique
10.4	Finishes and fit out	Materials will be brought to site by truck and lifted using crane.	18 months	Common construction technique
11	Enhancement of the fishponds at Lok Ma Chau	A water management system comprising an arterial pipe is to be installed, together with some modifications to the pond bunds to form the required habitat.	3 years	Common construction technique. Uses traditional labour, farming methods and equipment
11.1	Formation of the marsh	Reworking by machine of the bund material placed during station formation.	2 months	Common farming technique
11.2	Installation of the water control measures	Installation of steel sheet piles, installed by vibrating in to position, and excavation of the bunds by machine.	2 weeks for each location	Common construction technique
		Bring to site by truck precast concrete catchpits, culverts, channels, lifted into position by small crane.	2 weeks for each location	Common construction technique
		Laying of uPVC pipes into the ponds by hand.	1 week for each location	Common construction technique
		Backfill around catchpits with bund material, compacting by machine, and withdrawal of sheetpiles by vibrator.	1 week for each location	Common construction technique
		Excavation by machine of a shallow trench to install uPVC pipes forming the arterial system, backfilling with bund material.	1 month in each half	Common construction technique
11.3	Modifications to the bunds	Use of an excavator to lower the bunds, spreading to one side as required.	3 days for each location	Common farming and construction technique
		Import of 10mm aggregate by truck, placed by machine on a geotextile.	1 day for 100m	Common construction technique
11.4	Construction of the pipe bridge	Installation of gabions in the pond, with materials brought to site by truck and placed by machine.	1 week	Common construction technique
		Installation of timber piles brought to site by truck, by vibrating in to position by machine.	1 week	Common construction technique
		Installation of timber walings, and backfill by grade 200 fill brought to site by truck and placed by machine.	1 week	Common construction technique
		Installation of steel sheet piles, installed by vibrating in to position, and excavation of the bunds by machine.	2 weeks for each abutment	Common construction technique
		Installation of precast concrete bankseats, brought to site by truck and lifted by machine. Backfilled with bund material and compacted by machine.	1 week	Common construction technique
		Fabrication of the timber deck off site, brought to site by truck and lifted into position by crane.	1 week	Common construction technique
12	Shenzhen River Footbridge (Anticipated form of Construction)	This is a cable stayed structure design and built by the Mainland Authorities, with bored pile foundations in the river bed.	2 Years 9 months	Common construction technique. See KaiTak footbridge
12.1	Foundations	Install a cofferdam in the river by sheet piles, working from a pontoon moored in the river. Dewater the cofferdam by pumping.	3 months	A combination of usual methods and practices. LMC Boundary crossing used same cofferdam
		Erect a platform on the cofferdam and place a bored pile rig on it. Moor a pontoon alongside as support	1 month	A combination of usual methods and practices
		Construct the piles in reinforced concrete brought to site by barge.	2 months	A combination of usual methods and practices
12.2	Tower	Construct the tower in reinforced concrete by self climbing formwork with materials brought in by barge, to tower top level.	4 months	A combination of usual methods and practices
12.3	Deck erection	Pre-fabricate the deck segments and bring to site by barge. Lift into place from a tower top anchorage using strand jacks. Secure in position.	2 months	Common construction technique
		Lift successive segments of the deck using strand jacks mounted on the deck already constructed, securing to the permanent tower top anchorage.	2 weeks for a pair of segments	Common construction technique
12.4	Ship Impact Protection	Install ship impact protection and remove the temporary cofferdam.	3 months	Common construction . See Ting Kau Bridge.
13	Temporary Jetties in the Shenzhen River	Temporary piles with a steel deck.	4 months	See Shenzhen and Tuen Mun developments
13.1	Foundations and deck	Establish a mooring for a pontoon. Mount the piling rig on the pontoon and construct bored piles with permanent casing filled with reinforced concrete to river bed level. All materials will be brought to site by barge. Install the deck by welding supports to the pile top casing and attaching the decking by welding.	4 months	A combination of usual methods and practices
13.2	Dismantling	Remove the deck by flame cutting, lifting the detached parts onto a pontoon moored at the jetty. Cut of the steel casings at river bed level and remove by pontoon.	1 month	A combination of usual methods and practices
14	Temporary access roads	These will be aggregate laid on a geotextile if necessary
14.1	Temporary access roads on cleared land	The road will be 7m in width, comprising 500mm stone brought to site by truck, tipped and pushed into place by an excavator. A geotextile will be placed if ground conditions warrant this.	100m/day	Common construction technique
		To avoid impacting overland flow, the road will be either depressed into the ground, which will require the removal of existing soil, or placed on the existing ground and arrangements made to allow the overland flow to traverse the road. This could be pipes through, or a cut-off trench alongside the road. These measures are as stated in the DIA, and agreed by DSD.		Common construction technique
14.2	Access roads through ponds	The pond will first be drained. A geogrid will be placed and stone brought by truck and placed to the required level.	30m/day	Common construction technique LMC Boundary crossing site
		On completion of the works, where there is no requirement for a permanent bund, the temporary bund will be removed.		LMC Boundary Crossing sets precedent
15	Contractors Compounds	Compounds are required at various locations.		Common to all sites
15.1	Formation	The compounds will be graded to the required level, covered in a geotextile and stone placed to form a relatively flat competent surface.	2 months	Common construction technique
15.2	Compound Facilities	Temporary site offices for staff and containers for storage of materials will be erected. An electrical supply from either the network or a generator will be made, and a water supply will be laid. There will be latrine and washing facilities.		Common construction technique
		Plant maintenance and repair facilities will be put in place.		Common construction technique
		A precasting yard for smaller concrete items may be set up.		Common construction technique

13.6 Sundry structures and features for which piling, excavation or concreting works will be required are necessary will be carried out according to the principles of he major elements described above.

13.7 None of the technologies to be used in the construction of the Spur Line are un proven. The three major elements of the works have directly relevant comparable projects in Hong Kong, namely:

· the DB 320 bored tunnel contract for West Rail, for which the equipment and personnel will migrate to the Spur Line. Groundwater is not an issue for the TBM in earth pressure balance mode and fail safe measures in the form of an existing WSD inflatable dam are available to guarantee that the agriculture and wetlands in Long Valley will not be compromised;

· the station platform will have to be constructed over very soft ground at Lok Ma Chau. The Lok Ma Chau Boundary crossing platform and Boundary Crossing Facilities constructed in 1988 – 1992 successfully used blanket drainage, 2000km of vertical wick drains and reinforced earth technology and embankment surcharging to prepare the platform;

· the station and immigration facilities to be constructed on this platform have numerous comparable examples constructed in Hong Kong over the last 25 years; and

· the KCRC West Rail project has constructed the entire length of viaduct from Ho Pui to Tuen Mun, including a high level crossing of the Kam Tin channel.

13.8 The programme, construction methods and technology to be used in the construction of the Spur Line are all well proven in Hong Kong.

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