Site investigation is required to determine the engineering properties of soil and rock and how they will interact with a planned development. The purpose of site investigation is to establish parameters for foundation and substructure design; and to assess the potential contamination risks to humans, property and the environment.
The design and scope for each investigation will depend upon site-specific circumstances like the anticipated geology, previous use of the site and the construction proposals. There are a variety of techniques and procedures that may be used, and each consultant may adopt a different approach for any particular project. However, it is typical for the investigation to be carried out as a phased exercise, generally comprising:
Phase 1 — desk study
Phase 2 — intrusive investigation
Phase 3 — remediation strategy
Phase 4 — validation
The information obtained from each phase is assessed to ensure the initial objectives of the site investigation are satisfied. Changes to the scope of the investigation or even the design proposals and construction works, might be needed in the light of any unexpected findings.
The terms ‘site investigation’ and ‘ground investigation’ are frequently confused. A site investigation involves the collation of desk study information; appraisal of the data; assessment of the ground conditions; and the provision of an interpretative report. A ground investigation is broadly a more restrictive phase of specialist intrusive geotechnical investigation with associated site monitoring, testing and factual or interpretative reporting.