This award recognises projects that have delivered geotechnical innovation that stands out on the international stage for credentials in sustainability, health and safety and value engineering. In reaching their decisions the judges will take particular note of client satisfaction, innovation, value for money, performance against prediction, the quality of design and construction, safety and application of quality management.
bam ritchies cmyk
Aecom, Piling Contractors and Bauer Australia JV (PCBAJV)
Crown Sydney Hotel Resort, Australia
crown plaza hotel
PCBAJV designed the perimeter retaining walls and foundations for three-level underground basement and podium of a 75-storey tower adjacent to Sydney Harbour.
The detailed design and construction included the perimeter retaining walls for the basement using diaphragm wall techniques and all in-ground structures including core barrettes, foundations of the main tower and permanent plunge piles/columns. The design was required to support a full top-down construction of the podium and basement. Over 130 bored and sleeved piles were also designed and built for the terrace structure.
AS Tallina Vesi, United Utilities and Lemminkäinen
Tihase Kollektor Tunnel collapse, Estonia
repair of the collapsed tihase kollektor tunnel
The partial collapse of the 800m Kollektor tunnel in Tallinn caused major subsidence at the surface and interrupted the waste-water network.
The historical construction, weak water-bearing ground and prevailing weather conditions ensured a challenging emergency repair which included a sheet-piled cofferdam, jet grouting to support the tunnel and shaft, as well as tubes a manchette grouting to provide low permeability soil around the distressed tunnel. A second phase of grouting was undertaken to stabilise the existing tunnel outside the cofferdam and control groundwater control.
N71 “Moll’s Gap” retaining wall failure, Ireland
When a 200-year-old, 7m high section dry stone wall collapsed on the N71 in County Kerry in 2016, the varied ground conditions, steep topography, restricted access and remote location made this a challenging project.
A soil nailed slope solution with rigid shotcrete facing was adopted to remediate the retaining wall and stabilise adjacent sections. This solution met with Irish highways standards, improved the capital lifetime costs and delivered environmental benefits of reduced excavation and material usage - all with a 120-year design life.
Copenhagen Metro Team: Salini Impregilo - Tecnimont - Seli JV
Copenhagen Cityringen Metro, Denmark
The protection of historic buildings during the tunnel boring machine drive for the construction of a new underground line in the city was the most challenging aspect of this project.
The 16km twin tunnels were bored 1.5m above the existing metro tunnels and beneath an historic shopping mall - only 3.7m from its foundations.
Using a combination of mitigation measures including compensation and jet grouting, the project was able to limit any settlements to the mall and historic and vulnerable buildings adjacent to the tunnel alignment.
KFS Keller Kreate
Ratina Shopping Centre, Finland
ratina finland 2
When Keller was asked to replace all the sheet pile walls close to the existing buildings that made up Ratina, which is the largest shopping centre in Tampere, it suggested an alternative design.
Jet grouting is a well-known technique in Finland, but is rarely used for the underpinning of existing buildings. Finnish designs are conservative with small diameter columns, so the project’s 15m deep excavation pit put the designers in a difficult situation. Keller suggested drilling with 2m diameter columns – to limit the total number of holes – and use of the acoustic method.
Metroselskabet and Cowi Arup Systra JV (CAS JV)
Copenhagen Cityringen Metro, Denmark
arup cowi copenhagen cityringen metro, denmark 2
The new underground metro 16.6km circular line in the city includes the excavation for 17 new underground stations, five shafts and 34km of tunnelling. The project required more than 500 boreholes, the design of ground water control systems and complex structural monitoring.
Mixed face tunnelling risked significant impact on existing buildings and infrastructure, so tunnel alignments were optimised through sensitive low cover areas, combined with structural monitoring and localised ground movement mitigation to allow the tunnelling to be constructed, producing settlements below expected values and with no damage to the buildings above.
Opus International Consultants
Kaikoura earthquake response, New Zealand
On 14 November 2016, a MW7.8 earthquake struck Kaikoura causing extensive damage. Land access to Kaikoura was completely severed and Opus was responsible for managing NZ Transport Agency’s Response and Recovery phases – a project to reinstate highway access in to/out of Kaikoura.
Within 24 hours, geotechnical specialists were assessing the extent of the damage in helicopters, and developing action plans for clearance. Opus engineers in the region provided immediate on-the-ground updates and internationally based geotechnical engineers were relocated. Within two weeks the inland access to Kaikoura was reopened.
Waterview Connection, New Zealand
The country’s largest and most ambitious road project to date, Waterview Connection included twin 2.4km long, three-lane motorway tunnels.
Due to challenging soil conditions, it was decided to undertake shallow tunnelling that required a TBM that could operate in all ground conditions and resist potential high ground inflows while maintaining possible ground settlement. After constructing the first tunnel, the TBM was turned 180° in the northern portal cut and cover shaft to complete the second tunnel.