Geo-Technical Investigation

• Site investigation is the first step in solving most geotechnical engineering problems. Sometimes it allows the geotechnical engineer to optimize the design and propose less expensive options.

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• The objective in sampling a soil or rock deposit is to obtain samples that have the least amount of disturbance. The level of the groundwater at a site is a very important piece of information for any geotechnical investigation. All these information can be gathered only after drilling at the site.

• The Standard Penetration Test (SPT) is an in-situ test that is carried out in boreholes. The test will measure the resistance of the soil strata to the penetration undergone.

• The test is extremely useful for determining the relative density and the angle of shearing resistance of cohesionless soils. It can also be used to determine the unconfined compressive strength of cohesive soils.

• The load carrying capacity and extent to which a soil undergoes settlement under a given load must be known beforehand in order to design a foundation for the structures.

• In the field the ultimate bearing capacity and corresponding settlements can be determined with the help of Plate Load Tests (PLTs).

• The in situ density of natural soil is needed for the determination of bearing capacity of soils, for the purpose of stability analysis of slopes, for the determination of pressures on underlying strata for the calculation of settlement and the design of underground structures.
   

• Field Density Test helps in determining the in situ density of natural or compacted soils using sand pouring cylinders.

• Soil resistivity is a measure of how much the soil resists or conducts electric current. It is a critical factor in design of systems that rely on passing current through the Earth's surface. An understanding of the soil resistivity and how it varies with depth in the soil is necessary to design the grounding system in an Electric Substation for lightning conductors.

• It can also be a useful measure in agriculture as a proxy measurement for moisture content.