Overview
During the prolonged and heavy rainfall brought by Storm Bert in December 2024, the town of Merthyr Tydfil, Wales, experienced a dramatic ground collapse in a residential cul-de-sac.
A 10 metre-wide, 12 metre-deep crater opened at the bottom of a driveway in Nant Morlais, Pant, forcing the evacuation of around 30 homes. The sinkhole engulfed part of the road, pavement, and private drive, drawing widespread media attention.
The sinkhole resulted from the collapse of an old underground culvert. The structure failed after a landslide further up the valley washed debris through the culvert during the storm, triggering its collapse and subsequent ground failure above.
As an immediate safety measure, main contractor Edwards Diving Services undertook emergency works to backfill the void with stone, stabilising the area and preventing further subsidence, whilst also allowing time for a detailed long-term repair plan to be developed and approved.
Our Involvement – Silent Piling in a Residential Setting
To support the permanent repair phase, Ivor King was appointed by Principal Contractor Edwards Diving Services to design and install a sheet pile cofferdam around the affected zone. Given the tight residential environment, the project required an innovative approach to minimise disruption to local residents.
Working just centimetres from occupied homes, our team deployed Giken’s Silent Piling System – a state-of-the-art, vibration-free, and ultra-low-noise piling solution. We installed 14-metre ArcelorMittal steel sheet piles using a reaction-based pressing method, eliminating the need for traditional percussive piling and significantly reducing noise and vibration levels.
Key Advantages of the System
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Zero vibration – essential for proximity to residential structures
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Ultra-low noise levels – minimising disturbance to residents
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Compact footprint – ideal for confined urban environments
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Self-propelled mobility – allows the rig to ‘walk’ along installed piles efficiently
Once the cofferdam was in place, excavation within the secure structure could proceed safely. This provided a controlled environment for permanent culvert repairs, supported by hydraulic bracing to maintain structural integrity throughout the works.
Outcome
The project successfully stabilised the site, protected nearby properties, and enabled permanent remediation of the damaged culvert, without disruption to the surrounding community.
This operation stands as a testament to how specialist engineering techniques and careful planning can deliver low-impact, high-performance solutions, even in sensitive residential environments.
