This category is for projects with a geotechnical value of less than £500,000 that demonstrate innovative design, value engineering, stakeholder and community involvement and efficient delivery.
Atkins: The Moors at Arne, Coastal Change
The Environment Agency (EA) is proposing to create an intertidal wildlife habitat on the Arne Peninsula in Dorset. The project includes approximately 4.2 km of new embankments, water management control structures, public access roads and vehicle maintenance access. It will also include a new network of man-made streams, habitat islands and an intertidal lagoon system to enhance habitat diversity.
Atkins supported the EA to overcome geotechnical design challenges for the environmentally friendly project. The primary drivers of Atkins’ design were to maximize the use of site-earned material; minimal impact on existing biodiversity; natural displacement and preservation of existing habitats; minimize carbon emissions.
Embankments should have low enough permeability to act as tidal defences. Harsh soil conditions including soft organic clays, peat, and shallow groundwater prevail, but are variable in their occurrence. The embankments that surround the proposed intertidal lagoons will be periodically topped, so flooded, normal, and rapid design cases have been considered in the design.
Bachy Soletanche: Isle of Man Ferry Terminal, Liverpool
Bachy Soletanche has been subcontracted by John Sisk to install 14 ground anchors for the new Isle of Man ferry terminal in Liverpool on the banks of the River Mersey. A 3D design model was developed with the designers of the project to ensure that the anchors avoid the piles of the new terminal.
A 90t long reach excavator fitted with a high frequency sonic drill was used to reduce the load on the existing quay wall and advance the borehole up to 32m through man-made obstacles and boulders. A 3D alignment survey tool was used to verify the as-built drill position of the anchor prior to installation.
All anchors met the required tolerances and passed their subsequent independent pull-out tests. Environmental safeguards were put in place to protect the Mersey during the works and various innovative plant elements were used to eliminate manual handling.
Bam Ritchies: Tilbury Fort Anchor Inspections
Climate change is one of the main targets of the Environment Agency (EA), which is why Bam Ritchies was asked to ensure that the historic ground anchors that today hold the defenses against the floods will still be suitable for work in 20 years. The anchors were on the vertical face of a sheet pile flood barrier and within the tidal range of the River Thames. As a result, the team had to overcome access challenges, working tides, aging assets and the unknowns associated with ground anchor inspections.
Bam Ritchies worked with its supply chain as well as the EA and its designer to identify early on the toolkit of solutions needed to meet the challenges of the project. Using expertise from other disciplines in its business, the company has successfully developed an approach that allows it to maximize windows of work from a safe location and overcome the unknown challenges frequently posed by aging anchors.
Bam Ritchies: tall barns
Bam Ritchies was appointed in November 2021 to provide stabilization of an abandoned mine shaft at Hemel Hempstead and the empty ground associated with its perimeter. The key to the success of the project was to avoid any collateral damage to adjacent properties and to keep the local community on its side. He used his established relationships with Dacorum County Council, Arcadis and the community to engage these groups prior to contract award. In doing so, he developed feasible and deliverable solutions that achieved the required results.
Bam Ritchies believes its approach to this project demonstrates its consistent approach to creating value for its customers, as it took on the challenge of supplying bespoke equipment to complete the work in a tight residential location. He succeeded in taking the guesswork out of injection by applying integrated digital systems that enabled informed decisions and visibility of underground workings.
Bam Ritchies: Dinorwig
In August 2021, Bam Ritchies was approached by First Hydro Company (FHC) with a working list of stabilization requirements at Dinorwig Power Station, primarily in the access tunnels. He made several visits to the plant over the following years to deliver the planned work. In 2021, Bam Ritchies took care of the tunnel known locally as the ‘Series 10 Tunnel’ where the scope of work was to install 310 rock bolts 3,700mm long.
She delivered the job successfully the first time, while ensuring the safety of the project. It has eliminated hand-arm vibration, greatly reduced manual handling and avoided any impact on FHC operations.
Bam Ritchies’ ongoing relationship with FHC and the visibility it has given the contractor on future work allows it to make informed decisions for the future, particularly in the acquisition of plant and equipment. This ultimately gives him certainty and predictability in the delivery of their works.
Combined Soil Stabilization: Tattenhall Phase 3
The use of lime-modified embankments to improve soils to successfully support commercial structures is widely recognized. However, using the technique to support residential structures is less widely adopted. The project team behind Gifford Lea retirement village in Tattenhall, Cheshire, have been unable to determine an example of this approach to residential development in England.
Combined Soil Stabilization has been appointed to carry out the earthworks at Tattenhall. By adopting different techniques backed by strong performance specifications and validation requirements, it has provided a robust and cost-effective soil stabilization solution for residential development.
The company says the Tattenhall project is one of the first two: it shows the successful use of lime to improve the soils of a residential development and is the first such project to receive a full warranty from the company. ‘industry.
Concept Engineering Consultants: South Molton Triangle
Concept Engineering has been appointed to carry out a geotechnical and geo-environmental investigation and comprehensive structural study of the properties in the South Molton Triangle – a mixed-use development in London’s West End. The investigations aimed to support the design of new buildings, basements, underpinning and maintenance of facades, as part of a new redevelopment of the district.
The investigation included several boreholes that needed to be drilled in the area, a few of which required the under-shoring of coal vaults and the construction of bespoke scaffold pads, to support the drill pad above a skylight. A detailed fabric survey and ground-penetrating radar scan of the building facades was used to determine the composition and thickness of the front-facing building facades, which were used to assist in the design and to the support of the preserved facades.
Dywidag: Stone Cottage, Herefordshire
A storm in February 2020 caused significant damage to the busy B4224 road between Fownhope and Heresford. Dywidag and its partners have successfully completed the complex reconstruction of a collapsed rural stone retaining wall and road adjacent to a stone house. The site-specific conditions challenged the team to come up with creative and innovative solutions: one side of the road had to remain untouched as it included a functioning gas line and pedestrian access, and a protected garden with limited accessibility.
A new wall should be constructed while supporting the existing highway and upper slope. Dywidag, together with its partner Huesker, has developed an innovative hybrid system of soil nails and high-strength mesh geogrids to stabilize the slope. It served as a temporary support while difficult excavations were completed, with construction partner Alun Griffiths providing reliable long-term repair.
Geobear & Amey: treatment of the slab track in Kentish Town
Working with Amey, Geobear’s engineering team produced an innovative design solution to stabilize a slab section of railway track between Kentish Town Station and St Pancras Station in London. There was a significant geotechnical challenge where the slab track had suffered rapid deterioration which was manifested by cracking of the concrete slab in many places.
A design solution was devised that would use one of Geobear’s expansive geopolymer materials, injected under the slab, to reinforce the subsoil. The pattern, depth and control of the geopolymer material was essential to stabilize the area with minimal effects on the existing asset.
The asset life was extended to 15 years and the program was executed in a short period of time, reducing the period that line speed reductions were in place and associated delays conventional replacement.
Piledesigns: Foundation solution for a historic open pit marl backfill
As part of a redevelopment of a project in Hanley, Stoke on Trent, Piledesigns were appointed to provide geotechnical design, advice and approval for a suitable foundation solution.
The development of this site posed a number of challenges for the design of pile foundations, such as the presence of “high walls” along the edges of the open works where the piles could be deflected to the sides. There was also uncertainty regarding the interlocking lengths of the piles driven into the underlying solid strata.
Working with Hawk Developments and In-Situ Site Investigation, Piledesigns redesigned the foundation solution based on sound engineering and geotechnical principles as well as 3D modeling techniques. The solution was to use repurposed steel tubing, which required no major excavation or removal of material off-site, thereby reducing carbon emissions from construction.
Tobermore: Closing Latches, Darlaston
Tobermore was appointed by contractor Engie to reinforce a dangerously unstable brick wall at the rear of a social housing estate in Darlaston, West Midlands. The brick wall, located on the Latchs Close social housing site owned by Clarion Housing Group, was built directly on the ground without a concrete foundation.
Following consultation with Tobermore civil engineering consultants, Engie proposed to install a Secura Grand retaining wall as a solution to reinforce and stabilize the existing wall. Rather than replacing the entire wall, the existing wall and its wooden buttress were incorporated into the retaining wall designs, restoring the land for residents and property managers.
Following the retaining wall, the area of the estate that was previously cordoned off is now reopened to residents.