What is included in a geotechnical report?
A geotechnical report summarizes site conditions and provides engineering recommendations for design and construction. It typically includes the project background, site location, scope of work, and the standards or codes used (e.g., ASTM/ISO practices). It also describes the investigation methods used to characterize subsurface soils and rock, such as boreholes, test pits, sampling, groundwater measurements, and in-situ tests (e.g., CPT, SPT, vane shear).
Key technical content and findings
Most reports present the subsurface profile and soil/rock properties, including soil classification, stratigraphy, index properties, strength parameters, compressibility/settlement parameters, and permeability/hydraulic conductivity where relevant. Groundwater conditions are documented (depth, seasonal variation if known), along with any observed groundwater flow or seepage. The report usually includes laboratory test results and correlations used to derive design parameters. It may also address geologic hazards such as expansive soils, liquefaction potential, slope stability concerns, erosion risk, and fill material suitability.
Design recommendations and limitations
Geotechnical reports provide design recommendations for foundations (e.g., bearing capacity, allowable loads, settlement estimates, foundation type selection), earthworks (e.g., excavation support considerations, compaction requirements, grading and drainage), and retaining structures (e.g., lateral earth pressures, wall design parameters). They often include construction considerations, monitoring recommendations, and mitigation measures (e.g., dewatering, ground improvement, stabilization). A limitations section clarifies the report’s assumptions, investigation extent, and how results should be used, plus any required follow-up testing.