Geotechnical Investigations are normally undertaken to provide data for foundation or road pavement design.
Like a contamination investigation, geotechnical investigations should include a desk study. This can highlight parts of the site which may have been disturbed by previous development (such as backfilled basements), or which may be affected by difficult geological conditions (such as peat).
Intrusive investigation is again undertaken using a combination of trial pits and boreholes. In-situ tests such as standard penetration tests (SPT), dynamic probing, and hand shear vane tests may be undertaken. These can be supplemented by laboratory testing such as Atterberg limits (plasticity), tri-axial compressive shear strength testing, and compaction studies.
Chemical testing (sulphates, sulphides and pH) is undertaken in accordance with BRE Special Digest 1: Concrete in aggressive ground. This allows the correct design class to be specified for sub-surface concrete structures (such as foundations).
On completion of laboratory testing EMS produce full interpretative reports, including recommendations for foundation and floor slab design.