A ground investigation was required to provide geotechnical data and investigate potential mining beneath the site with specific regard to any potential mining risk associated with the proposed infilling works to an underbridge.
Desk study information indicated that limestone had been extracted from beneath the site and the ground investigation was required to determine if workings were present, the thickness and quality of rockhead above the workings along with the thickness of superficials. Specifically the investigation was to investigate the Great Mine, Four Feet and Yard Limestone beds.
The work was carried out using a combination of cable percussive boreholes with rotary follow-on using our in-house Fraste multi-purpose drilling rig with Geobor – S capability with water flush and continuous gas monitoring.
All works were supervised on a full-time basis by suitably qualified in-house Engineering Geologists.
Geotechnical logging was carried out to BS5930: 2015+A1:2020, BS EN ISO 14688 [Parts 1 and 2] and BS EN ISO 14689 with detailed discontinuity spacing records and particular care to record any zones of weakness or disturbed strata that might indicate backfilled or collapsed limestone beds that had been mined.
The program of works included: