Geotechnical investigations are performed to obtain
information on the physical properties of soil and rock
at site to design foundations for different structures
and for repairing or renovation of distress earthworks
and structures. Geotechnical investigation includes
subsurface exploration, conducting some field tests
and collection of soil samples.
To obtain information about the soil conditions below
the surface, some form of subsurface exploration is
Methods of observing the soils below the surface, obtaining samples, and determining physical properties of the soils and rocks include test pits, trenching (particularly for locating faults and slide planes), boring, and in situ tests. Reliability and accuracy are the essence of geotechnical investigation. Comprehensive, precise, detail and reliable investigation can reduce construction cost and time. On the other hand, unreliable geotechnical parameters always deceive or betray engineers and entrepreneur.