What a geotechnical investigation tells your foundation designer
A geotechnical investigation converts unknown ground conditions into design information. The useful output is not simply a borehole log. It is a coordinated record of what was found, how it was tested and what those findings mean for the proposed structure.
Start with the proposed development
Investigation depth, spacing and test selection should respond to the building footprint, anticipated loads, foundation options and site constraints. A residential block, water tank and road embankment do not ask the ground the same questions. Early drawings and loading information help the geotechnical engineer design a proportionate scope.
Build evidence from several methods
Boreholes describe the soil and rock profile at depth. Trial pits expose shallow materials and existing fill. SPT and DCP results provide field indicators of resistance, while laboratory testing measures properties such as grading, moisture, density and strength. Interpretation is stronger when these records support one another.
Use the report as a design input
The final report should identify the investigation locations and methods, present factual records, explain the interpreted ground model and state limitations. Foundation designers use this information to compare options, assess settlement and excavation risks, and define any further work needed before construction.