Peel Ports has started construction on Liverpool2, a landmark deep water container terminal which will be open for business in 2015.
The £300 million in-river container terminal will see vessels up to 13,500 twenty-foot equivalent units (TEU) able to call directly at the Port of Liverpool. The 17 hectare (ha) terminal will be sited on the southern side of the Royal Seaforth Dock, adjacent to the outer Mersey estuary
The development site extends from the south west corner of the Royal Seaforth Dock to the northern riverward knuckle of the Gladstone River entrance. The scheme will deepen the River Mersey approach channel from its current 6.9 metres (m) below chart datum (bCD) to 8m bCD. The intertidal area in this location is known as the Seaforth Triangle.
In 2005 an environmental statement (ES) was produced to support the harbour revision order (HRO) application to give Peel Ports the necessary powers to construct the terminal. Supplementary information to the 2005 ES was produced in 2006. The scope of the 2005 ES comprised an assessment of the terminal construction and operation and dredging of the approach channel. Prior to the granting of the HRO, a total of 63 agreements and obligations were drafted or entered into by Peel Ports with various groups and organisations. The HRO was granted in May 2007.
The ES specifically addressed the requirement of a marine licence application for the proposed works below mean high water springs (MHWS). It focused on the predicted impacts of the marine works together with the findings associated with the assessment of the deepening of the Mersey approach channel, and was refreshed in 2012. The Marine Management Organisation granted a marine licence in December 2012 which effectively green-lighted construction of the works as defined under the HRO and supported by the ES.
Improved access
The Liverpool2 scheme will provide a terminal which will allow access to the latest generation of post-Panamax container vessels and will be capable of handling up to 600,000 TEU per annum. In order to provide the necessary container handling and storage area to serve Liverpool2, Peel Ports will reclaim the Seaforth Triangle area. This reclamation will cover an intertidal area of 12ha to mean low water (MLW) (0m CD). The infilling of the area behind the quay wall will begin over the northern portion of the site after approximately 50 per cent of the quay wall has been constructed. Approximately 850,000 cubic metres (m3) of dredged material will be removed to form the berth pocket, and this dredged material will then be reused in the reclamation works. The overall programme for the construction of the quay wall, the reclamation and associated dredging of the adjacent berthing pocket and channel dredge will take two years to complete, with an overall investment of in excess of £300 million.
Peel Ports will also deepen the River Mersey approach channel from a minimum existing depth of 6.9m bCD to 8.0m bCD. This will enlarge the tidal window through which vessels will be able to access the berth. The approach channel has been previously dredged and maintained at 8.0m bCD and cleared of all wrecks below this level. The programme of capital dredging will start in September 2013 and will take up to 12 months to complete. A new 854m length of quay wall with a quay surface at 12.7m above chart datum (aCD) will be constructed. Capital dredging in front of the new quay wall to 16.5m bCD to create a 62m wide berth pocket will permit post-Panamax vessels of up to 14.5m draught to berth in the pocket. Reclamation of the Seaforth Triangle area behind the new quay wall will use more than 2 million tonnes of dredged material from the capital dredging operations. The terminal will benefit from the provision of eight ship-to-shore cranes (STS) having a 50m outreach and twenty seven semi-automated cantilevered rail mounted gantry cranes (RMGs) with a 12 wide/6 high operating capability as well as the latest generation of fully integrated terminal operating systems.
The plan
The new quay wall will be a combi-piled construction solution formed from 2m diameter 40m long steel (tubes) piles with sheet steel piles acting as infill panels between the steel tubes. Prior to the installation of the piles a dredging programme will remove the alluvial silts and underlying clays using a trailer suction hopper dredger and a backhoe dredger. Large backhoe and water injection dredging techniques will prepare the foundation for the new quay. With the underlying sand and gravels exposed, jack-up barges will be used as temporary works piling gates to temporarily support the piles. The piles, at 40 tonnes each, will be lifted into place and held in position by the gates. They will then be vibrated through the sands and gravel to toe into the sandstone rock formation. A pile top drilling rig will auger materials from within the pile and drive the pile to its final toe design level. Large percussion hammers will drive the pile to act as a semi cantilever. A similar process will be adopted for the installation of the sheet pile infill panels. The main anchor wall behind the quay wall will be piled with high tensile tie bars placed to connect the walls in parallel. The quay wall capping beam will be pre-cast on site and will accommodate the quayside services, furniture and fendering.
Dredged material will be hydraulically placed by pumping ashore in suspension through pipework from a dredger for the infilling of the area behind the new quay wall The dredger will connect to the shore side delivery pipe to feed a spay pontoon for land reclamation, depositing material in layers for hydro compaction. In order to facilitate faster consolidation of the soft layers below the reclaimed area behind the quay wall, band drains will be installed to encourage accelerated drainage of the soil mix. To increase the pressure that is available to make the band drains work efficiently, a surcharge of reclaimed fill material will be placed temporarily above the reclamation and, when sufficient consolidation has been achieved, the material will be removed and used as filling.
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