CPT vs Boring and when to use each

Hi All,

A question came up in the Soil Analysis workshop today about when to use soil boring vs. when to use CPT. I wanted to do some further digging myself (no pun intended) so I could give you all an accurate response. So first, I’ll start with the definitions of each:

Soil Boring: a technique used to survey soil by taking several shallow cores out of the sediment. It is used when a drilling jacket or jack-up rig is to be supported on the soil. Conventional soil boring was used to determine the subsurface soil profile and static soil properties.
Cone Penetration Test (CPT): an in-situ test that is used to identify the soil type. In this test a cone penetrometer is pushed into the ground at a standard rate and data are recorded at regular intervals during penetration. A cone penetration test rig pushes the steel cone vertically into the ground. The cone penetrometer is instrumented to measure penetration resistance at the tip and friction in the shaft (friction sleeve) during penetration.

When to use each:
Standard boring testing is used in construction projects for the preliminary soil investigation. It’s an inexpensive test, the test can be done quickly, and it’s relatively simple to perform. CPTs are used for detail soil investigation and construction quality control. They are known to have increased accuracy and speed of deployment/results, they show a more continuous oil profile. They do tend to take more skill to perform and can be more expensive then standard boring tests.

Thanks everyone for a great workshop, I hope this information helps!

-Rebecca

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