Geophysical investigation techniques are non-invasive and can produce a full coverage of a site, often as part of the site reconnaissance phase of the investigation and combined with intrusive investigation.
Ruddlesden geotechnical work closely with specialist geophysical contractors to ensure the most suitable geophysical method is used, based on the site constraints, anticipated ground conditions and target of the investigation, e.g. historical mining features, voids (natural or man-made), tanks etc.
A variety of both surface and down-borehole methods can be used, including ground penetrating radar, magnetic, electrical resistivity and conductivity, and seismic reflection and refraction.
Geophysics Provides Site-Wide Ground Profile Information, Devon
Near-surface geophysics, comprising ground penetrating radar (GPR) and resistivity, was used to identify the presence, geometry and depth of limestone solution features at a proposed residential development site in Torbay.
Following a soakaway test investigation, Ruddlesden geotechnical had concerns that the natural solution features within the limestone bedrock could inhibit the use of conventional soakaway drains at this site.
Some conventional trial pitting and trenching had been undertaken with excavation plant, revealing a variable and often absent rock-head profile. Due to the variability and need to keep site disturbance to a minimum, geophysics was considered to be the most suitable method of investigation.
Ruddlesden geotechnical have a good working relationship with a specialist team of geophysicists, who, under the instruction of Ruddlesden geotechnical, completed the works on this project.
Following the geophysical survey and acquisition of the site, further geotechnical investigation was undertaken to confirm the profile (and depths) provided by the geophysics. The geophysics provided greater site coverage and certainty on the ground conditions, which were proven to be variable and potentially problematic.