A geotechnical investigation gathers field and laboratory information about subsurface conditions to inform a project’s design and construction decisions.
Definition
A geotechnical investigation is a planned program to learn about soil, rock, and groundwater conditions relevant to a project. It can include soil borings, sampling, in situ testing, laboratory testing, and groundwater observations. The scope depends on the questions the design team needs answered, the site, access, and project constraints. An investigation does not reveal every condition across a site. Its findings reflect the locations, depths, methods, and time of the work, so the report describes limitations and assumptions. Firms may define the scope by a set number of borings, test locations, or tasks, while clients may focus on particular design questions or deliverables. It is not the geotechnical report itself, a guarantee that no unexpected conditions exist, or a construction inspection program. Owners can use ASCE as a professional resource when considering the role of geotechnical work in project planning.
How owners use it
- Set investigation tasks and deliverables around the design questions, such as foundation support or groundwater conditions.
- Compare proposals by checking boring locations and depths, sampling, testing, access, and stated limitations.
- Coordinate site access, utility clearance, and restoration responsibilities before fieldwork begins.
- Example: 6 borings at 30 feet each gives 6 × 30 = 180 total boring feet for the planned program.
