Borehole

The word ‘borehole’ is: ‘The generalised term for any narrow shaft bored in the ground either vertically or horizontally.’ Ref Containment systems for the prevention of pollution, Secondary, tertiary and other measures for industrial and commercial premises (CIRIA C736), published by CIRIA in 2014.

High Speed Rail (Crewe – Manchester) Environmental Statement, Glossary, abbreviations and references, published by the Department for Transport in 2022, defines a borehole as: ‘A hole bored into the ground, usually as part of investigations, typically to test the depth and quality of soil, rock and groundwater. A borehole can also be used to dewater the ground.’

Rotary boreholes are used where drilled exploration through rock and other solid geological formations such as dense gravel is required. Depths of up to 100 m can be achieved and bedrock samples taken to a laboratory for examination.

Rotary open-hole boreholes are drilled where an understanding of the presence of voids is more important than the structural details of the ground, and are typically used in areas where mine workings are likely.

Rotary cored boreholes are drilled when the structural details of the underlying rock are required. A core barrel is lowered into the drilled hole and a flush circulated with air/mist or water.

[edit] Related articles on Designing Buildings

• Building on fill.
• CIRIA.
• Ground conditions.
• Ground improvement techniques.
• Ground investigation.
• Insitu testing of soils.
• Soil report.
• Soil survey.