The geotechnical or geo-environmental Site investigation comprises an initial Desk study comprising a review of the available historical information on the site including ordnance survey plans, geological maps, mining records, etc. followed or preceded by a walkover study also called the reconnaissance survey or site inspection. After this follows the intrusive site (or ground) investigation including trial pits, Boreholes sampling field or in-situ testing, laboratory testing and the main report.
A ground investigation is the intrusive or physical part of a geotechnical investigation. Ground investigations involve in-situ testing and or sampling the ground and ground water using trial holes or test pits, auger holes, Boreholes or drill holes. Geotechnical investigations are performed by Geotechnical Engineers or Engineering Geologists to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. This type of investigation is called a Site investigation. Additionally, geotechnical investigations are also used to measure the thermal resistivity of soils or backfill materials required for underground transmission lines, oil and gas pipelines, radioactive waste disposal, and solar thermal storage facilities. A geotechnical investigation will include surface exploration and subsurface exploration of a site. Sometimes, geophysical methods are used to obtain data about sites. Subsurface exploration usually involves soil sampling and laboratory tests of the soil samples retrieved.
Surface exploration can include geologic mapping, geophysical methods, and photogrammetry, or it can be as simple as a geotechnical professional walking around on the site to observe the physical conditions at the site.
To obtain information about the soil conditions below the surface, some form of subsurface exploration is required. Methods of observing the soils below the surface, obtaining samples, and determining physical properties of the soils and rocks include test pits, trenching (particularly for locating faults and slide planes), boring, and in situ tests.
Geoinvestigate provides a broad range of Ground Investigation Services.