The standard penetration test (SPT) is an in-situ test designed to provide information on the geotechnical
engineering properties of soil.
This test is the most frequently used subsurface exploration drilling test performed worldwide.
The test procedure is described in ISO 22476-3.
The test is conducted in a bore hole by means of a standard split spoon sampler.
Once the drilling is done to the desired depth, the drilling tool is removed and the sampler
is placed inside the bore hole. By means of a drop hammer of 63.5kg mass falling through
a height of 750mm at the rate of 30 blows per minute, the sampler is driven into the soil.
This is as per IS -2131:1963. The number of blows of hammer required to drive a depth of
150mm is counted. Further it is driven by 150 mm and the blows are counted.
Similarly, the sampler is once again further driven by 150 mm and the number of blows
recorded. The number of blows recorded for the first 150mm not taken into consideration.
The number of blows recorded for last two 150 mm intervals are added to give the standard
penetration number (N).
In this test, CiviLab supports the following standards: