Standard Penetration Test (SPT)
Standard Penetration Test (SPT)
The standard penetration test is an in-situ test that is coming under the category of penetrometer tests. The standard penetration tests are carried out in borehole. The test will measure the resistance of the soil strata to the penetration undergone. A penetration emphirical correlation is derived between the soil properties and the penetration resistance. 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 standard penetration test is an in-situ test that is coming under the category of penetrometer tests. The standard penetration tests are carried out in borehole. The test will measure the resistance of the soil strata to the penetration undergone. A penetration emphirical correlation is derived between the soil properties and the penetration resistance. 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 requirements to conduct SPT are: |
|
1. Standard Split Spoon Sampler |
|
2. Drop Hammer weighing 63.5kg |
|
3. Guiding rod |
|
4. Drilling Rig. |
|
5. Driving head (anvil). |
|
Precautions taken for Standard Penetration Test |
|
1. Split spoon sampler must be in good condition. |
|
2. The cutting shoe must be free from wear and tear |
|
3. The height of fall must be 750mm. Any change from this will affect the ‘N’ value. |
|
4. The drill rods used must be in standard condition. Bent drill rods are not used. |
|
5. Before conducting the test, the bottom of the borehole must be cleaned. |
