Geotechnics is a bridge between geology and civil engineering. It is a study of the substructure (sub soil) beneath the earth to evaluate and observe the engineering strength and properties of soils. It helps to determine the suitability or otherwise of the soil for Civil Engineering purposes either as footing or material for construction. Hence, the need for geotechnical investigations before the erection of superstructures either on land or water.
The purpose of the investigation is:
To provide geotechnical data from the field tests carried out.
Analyze the swelling and shrinkage potential of the soil
Find out the allowable ground bearing pressure as may be useful and relevant for the design of the foundation of proposed structure.
Recommend the footing depth on which the superstructure will stand
Provide necessary recommendations on suitable type(s) of shallow foundations.
To determine the nature and type of settlement expected.
Determine the ultimate bearing capacity of the soil.
Determine the suitability or otherwise of the soil as a construction material.
Give adequate recommendation on best depth for piling should need arise for deep foundation.