Contents of site investigation report

A site investigation report is the final record of the soil investigation. It must be clear enough for a designer who has never visited the site.

Contents

1. Introduction: project name, location, purpose, scope, date, and names of the client and the investigating agency.
2. Site description: topography, existing structures, drainage, access, nearby sources, geology, seismic zone, past land use.
3. Field work: number, location and depth of boreholes/pits, method of boring, sampling methods, field tests (SPT, vane, plate load, etc.).
4. Laboratory tests: grain size, Atterberg limits, moisture content, unit weight, shear strength, consolidation, chemical tests.
5. Subsoil profile: borehole logs, soil profile sections and the groundwater level, with soil classification (IS 1498/USCS).
6. Analysis and findings: design parameters ($c$, $\phi$, $\gamma$, $C_c$, $N$), safe bearing capacity and expected settlement.
7. Recommendations: type and depth of foundation, allowable bearing pressure, ground improvement, dewatering and construction precautions.
8. Appendices: site plan with borehole positions, bore logs, test results, photographs, and a reference list of codes used.

Things to consider while preparing it

• Use clear, brief language and standard symbols and units.
• Separate the facts (observed data) from the interpretation.
• Give the limits of the investigation and note the possible variation between boreholes.
• Present tables and drawings at a suitable scale and check them for consistency.
• Report the groundwater level and its seasonal variation.
• Make recommendations economical and practical for the construction methods.