Scour Protection and Effective Management of the New Deep Water Berth at Liverpool 2 Container Terminal
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Published:2018
Mr Garry Sharpe, Mr Daan Makkink, Ms Lizzie Chellew, Mr Paul Hesk, 2018. "Scour Protection and Effective Management of the New Deep Water Berth at Liverpool 2 Container Terminal", Coasts, Marine Structures and Breakwaters 2017, Kevin Burgess
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Abstract
The new Liverpool2 deep water container terminal on the River Mersey, by being able to accommodate two large post-panamax container vessels along a new 854m long quay wall, significantly expands the capabilities of the Port of Liverpool.
The new quay wall retains 16 hectares of newly reclaimed land which forms the terminal area. In front of the wall, a 62m wide berth pocket has been dredged to -16.5mCD, this requiring the existing bed to be lowered by up to 10m in a material consisting mainly of sandstone.
The western side of the dredge pocket has been formed with a 2:3 side slope in the sandstone and, in consequence, scour protection is not required. However, the 62m wide northern and southern sides have been formed with slopes extending into overlying layers of sand, gravel and glacial till and these required additional scour protection to ensure the 50 year design life.
This scour protection has been designed to be compatible with both the adjacent rock armour revetment and the existing quay wall at the entrance to Gladstone Lock. A desk study was undertaken to determine the contributory factors to scour within the new berth pocket and the stability of the rock protection proposed to be provided. This concluded that protection was required to mitigate the effects of propeller action during the berthing and un-berthing of vessels. In consequence, the scour protection has been designed to withstand the jet flows from the propellers of vessels for which this facility has been designed, as well as wave action at the emergent slopes of the transitions from the berth pocket to the existing river bed.
To the north, the protection of the berth pocket, quay wall, existing revetment and surrounding seabed is provided by the installation of a filter layer, secondary armour (300 to 1,000kg) and primary armour (4 – 6 tonnes). In addition, a falling apron, comprising filter material and secondary armour only, has been constructed. These works were undertaken by both marine and land based equipment. To the south of the berth pocket, the scour protection, 1 – 3 tonne armour overlying a filter layer, is fully submerged and therefore was undertaken by marine equipment only.
Wherever possible, the rock materials were recycled, with, for example:
The armour having been obtained from a section of existing rock revetment removed to allow the construction of the new quay wall; and
The filter stone having been selected from material dredged from the new berth pocket.
