GeoSonic Drilling was recently commissioned by Costain Environmental Services, on behalf of Aberdeenshire Council, to provide sonic drilling services as part of the ground investigation for the proposed Stonehaven Burn of Glaslaw and River Carron Flood Alleviation Scheme.
The exploratory hole locations were positioned across a 600m linear corridor through Stonehaven, which included main roads, narrow single lane side streets, parkland, residential properties, gardens and public areas.
Over 50% of the locations were subject to traffic management to provide a safe working environment.
The contract called for rapid, clean profiling of the underlying geology with as few rig movements as possible to mitigate costs arising from traffic management and disruption to residents.
The geology in this part of Stonehaven is dominated by granular alluvial deposits of the Holocene, and late Pleistocene sand and gravel formations, giving rise to potentially challenging drilling conditions.
GeoSonic provided continuous soil profiles for inspection by Costain’s engineering geologists. One benefit of sonic drilling is that the soil/rock interface, so often uncharacterised or misinterpreted, was able to be fully profiled.
Costain had a traffic management schedule for the whole site investigation, so any deviation from this would slow the works programme.
The site works were completed ahead of programme, and faster than if the project had been undertaken using conventional drilling methods.
Costain engineers directed the sampling regime and GeoSonic provided a range of undisturbed sampling methodologies, including the collection of Class 1 UT100 samples compliant with Eurocode 7, alternating with standard penetration tests performed by automated trip hammers.
Water containment measures were enforced at all drilling locations using bespoke equipment.
This prevented uncontrolled ground water discharge, and any water contained was disposed of via an approved waste route.