King Sheet Piling (KSP®) can be used for any retaining wall where the pile section chosen is governed by driveability and hence surplus structural capacity is available in bending. Shear is not normally a controlling factor. KSP walls can normally replace cantilever sheet pile walls, up to 4m high, sized for driving in typical UK soils. In low retained height walls in soft ground requiring only a light section, there may still be sufficient spare capacity for savings to be made using the KSP approach. Retaining walls designed in reinforced concrete may be more economical as KSP walls.
KSP is ideal where it is desirable to allow the flow of groundwater across the line of the wall or where groundwater is not a design issue. A KSP wall can also be used to advantage where a cut-off is required, either by lengthening the intermediates sufficiently to form a seal into a deeper, impervious layer or by forming another form of cut-off. This can be achieved by:
KSP walls are ideal for flood protection or beach erosion walls in ground where there is not a problem of significant seepage flow beneath the intermediates. KSP can produce an economical and rapidly installed flood protection wall in these circumstances. Potential concerns over erosion or scour to beneath the intermediates are easily satisfied (see Technical Guidance download).
KSP can be used as combined temporary works and permanent works support for culverts in compressible alluvium. Propped or tied-back KSP walls provide the temporary support during construction. Shear studs or equivalent are welded to the kings to transfer net vertical load from the reinforced concrete culvert to the kings, avoiding the need to pile the culvert.
Other variations include:
Basements, underground car parks or pumping stations that can be sheet piled are ideally suited to KSP, particularly where vibration-free pressing is used as this typically requires use of larger sections. The intermediates can extend to just below basement slab formation level with the KSP wall functioning as the permanent wall, with clutches welded for water-tightness. Alternatively, the intermediates can be taken down sufficiently to form a cut-off into low permeability strata, e.g. London Clay beneath Terrace Gravels. Other forms of permanent support can be provided for the clay between the kings and a false wall and seepage collection provided, as is often done with secant pile walls.
The greatly enhanced speed of installation is a major benefit in forming retaining walls for existing infrastructure in constrained working conditions. This especially applies to the rail environment, where possession time is crucial.
KSP walls for bridge abutments form an economic alternative to traditional abutments when cost, simplicity and speed of installation are taken into account.
8 June 2016: Up to 60% steel saved! 1.3 km of KSP walls on the A1 Coalhouse to MetroCentre Improvement achieved a new milestone, saving 44% steel on average, up to 60% steel on individual walls and 902 tonnes overall. The Arup design for Balfour Beatty included the first permanent works use of KSP walls with two pairs of intermediate piles.
15 September 2015: David Baker presented a paper entitled “King Sheet Piling (KSP) – a fundamental and innovative advance on past sheet piling practice” at the International Society for Soil Mechanics and Geotechnical Engineering’s XVIth European Conference on Soil Mechanics and Geotechnical Engineering in Edinburgh in September, 2015. This prestigious conference attracted over 1,150 delegates made up largely of leading practitioners from 65 countries.