Standard Penetration test details and Penetration types

Types of the Penetration test and its explanation

1. Standard Penetration test(SPT)
2. Static cone Penetration test
3. Dynamic Cone Penetration test

Standard Penetration test

SPT is a field test to determine the relative density of sandy soil and to find the allowable bearing pressure of soil

The test is performed on clean borehole 55mm to 150mmin diameter and supported on site s by a casing pipe.

split spoon sampler of 50 mm external diameter 35 mm internal diameter and 650 mm length is used in this test

The minimum length of the sampler is 16 centimeter and the sampler is connected to the end of Boring Rods

The sampler is driven into the undisturbed soil below the bottom of the borehole by means of a 65 kg hammer falling freely through a height of 750 mm

The sampler is first driven by 15 centimeters length, so as to sheet the sampler and to bypass any disturbed and at the bottom of the Borehole

SPT Value

The number of blows required to drive the simpler 30 centimeters beyond seating drive is termed as the Penetration resistance "N"

Correction to be absorbed N

1.over burden pressure

2.submergence

(Static Cone Penetration test and dynamic cone Penetration test update next)