Purposes of site investigation

Site investigation is the systematic collection, analysis and interpretation of geological, geotechnical and hydrological data of a site, to decide its suitability and to provide the information required for the design and construction of a civil engineering project.

Why geological site investigation is required

1. To select a suitable site or alignment among alternatives.
2. To find the soil and rock types and their sequence, thickness and extent.
3. To determine engineering properties: bearing capacity, shear strength, compressibility, permeability.
4. To locate geological defects: faults, shear zones, joints, cavities, landslides and weak layers.
5. To determine groundwater conditions: water table, seepage and quality.
6. To assess hazards: earthquake, flood, landslide, erosion and subsidence.
7. To design foundations, slopes and support systems economically and safely.
8. To estimate quantity and quality of construction materials.
9. To choose the construction method and equipment, and to estimate cost and time.
10. To prevent failures, unexpected costs, claims and delays in the contract.
11. To assess the environmental impact of the project on the ground.

Investigation is done in stages: reconnaissance, preliminary and detailed.