What is Ground Investigation?
27th September 2023
What is Ground Investigation and why is it necessary? Northpoint considers the main elements of both intrusive geotechnical and geoenvironmental surveys.
Before Starting a Ground Investigation
Northpoint carries out the preliminary phase of the investigation (Phase 1 Desk Study). This includes assessing available records and technical data. This allows Northpoint to provide robust geotechnical and geoenvironmental recommendations via a targeted Phase 2 Ground Investigation.
The initial Phase 1 is important as desk-based information is assessed In order to appropriately design the intrusive ground investigation phase.
Without the initial Phase 1, a construction project is at risk. For example, information may be lost and this could have time and cost implications for a build as things progress.
What’s involved in the GI?
It is recognised that ground for building on is a hazard without site investigation. Therefore with safety in mind, we undertake detailed intrusive site investigations. This ensures your project build is appropriately designed. Therefore a range of exploratory methods may be required to build a detailed ground profile model beneath a site. This could include a range of land drilling techniques, to trial excavations, specialist probing and insitu testing. We routinely gather soils and rocks beneath a site and analyse these in a laboratory to finetune our understanding of what’s happening in the ground.
The investigation also considers environmental constraints where land contamination is a problem. By contrast, a Geotechnical Survey may be as simple as a small subsidence investigation, bearing and settlement calculation. It can be more complex, through modelling slopes, embankments, cuttings. The geotechnical assessment looks at soil and rock strengths and properties, and how the ground can safely accommodate a structure (such as a house, office, bridge, road).
Northpoint routinely undertakes site investigation encompassing both geotechnical surveys and land contamination assessments. This is often referred to as a Geoenvironmental Appraisal.
In summary, the intrusive phase and characterising a site informs our Phase 2 Ground Investigation Reports. As a minimum we consider in our technical reporting:
- Detailed geotechnical assessment to inform design, such as foundations and roads through to sustainable drainage.
- Land Contamination assessment – determining if your project is at risk from hazardous substances like ground gases and contaminated material that may be harmful to health.
- Overall production of a ground profile that helps us develop a realistic Conceptual Site Model for a project. This is also used to satisfy both design and regulators.