Geotechnical reports show the site soil, rock and groundwater conditions to be used for designing foundations of all types of structures. They are prepared for each project, based on data obtained from subsurface investigation and soil testing and measurement, as discussed in the preceeding two subsections above plus other sources.
It is very important to prepare an adequate geotechnical report. This report is always referred to during the design phase, and even during construction phase. It can also be used after the construction is complete, if there are unresolved claims. The cost of preparing an adequate geotechnical report is far less than the cost of paying for claims resulting from inadequate reports. Due to its importance, these reports should be clear, concise and accurate. The minimum boring, sampling and testing guidelines have been established by federal and state agencies (i.e. FHWA for roads and bridges), and the reports must take those standards into account.
Geotechnical report include things such as:
- General information and description of site, results of site investigation, and interpretation of these by the geotechnical engineer
- A detailed summary of all subsurface exploration data, including soil classification, boring logs, subsurface profile, groundwater condition including measured dates
- Field and laboratory test results
- Soil borrow sources
- Recommendations by the engineer for the foundation to be designed and geotechnical features, including anticipated problems, such as, structure foundations, retaining structures, embankments over soft ground, landslides, earthwork (cut and fill of soil), ground improvement techniques, material sites, surface and subsurface drainage, erosion protection measures,
- Discussion of unusual and complex geotechnical problems, if any
In the next post of this series, we will discuss “Groundwater, Dewatering & Drainage, Seepage”