Standard penetration test (SPT)



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:

  • NF EN ISO 22476-3;
  • BS EN ISO 22476-3.

CiviLab allows you to calculate:

  • The coefficient CN;
  • The coefficient λ;
  • N60 and (N1)60;
Test sheet samples in PDF format Download the user manual for this test

Sample screenshots




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