Updated 29 November 2010
Outline
The cone penetration test (CPT) is a common in situ testing method used
to determine the geotechnical engineering properties of soils and
assessing subsurface stratigraphy. The test is also called, Dutch Cone test. Due to its simplicity and efficiency, the cone penetration test is one of the most commonly accepted and used in-situ testing methods in geotechnical investigation worldwide.
Description and test procedure
The cone penetration test (CPT) is a common in situ testing method used
to determine the geotechnical engineering properties of soils and
assessing subsurface stratigraphy. The testing apparatus consists of an instrumented still cone having a tip facing down, with an usual apex angle of 60° and cross-section area of 1000 mm
2. The code is attached to a internal still rode than can run inside a outer hollow rod, which itself is attached to a sleeve. In the more elaborate CPT instruments, the cone and the sleeve (attached to the outer rod) can move separately.
The Cone penetration test can be carried out from the ground surface with a need for a borehole. The test is carried out by first pushing the cone into the ground at a standard velocity of 1 to 2 cm/s while keeping the sleeve stationary. For any depth, the resistance of the cone, called cone penetration resistance
qc , is recorded using the force probes provided for this purpose in the cone. Then the cone and the sleeve and moved and penetrated together into the soil and the combined cone and sleeve resistance, indicated by
qt , is recorded at any depth using tension load cells embedded in the sleeve. This procedure is repeated and the measurements are made at regular depth intervals during penetration. In addition to the stress on the tip and the sleeve friction, the typical CPT probe
measures as well the porewater
pressure. Some equiped CPT probles are also able to measures shear wave
velocity and temperature.
The cone penetration resistance values can be then correlated to shear strength parameters using proposed empirical curves. There are also some design methods associated with CPT results which directly use the CPT results to estimate the settlement is soils under a given pressure.
Test Standards
- BS 1377-7:1990
- ASTM D3441 - 05 Standard Test Method for Mechanical Cone Penetration Tests of Soil Link
- ASTM D5778 - 07 Standard Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils Link
Related experimental results on Database
-
GDL011: CPT interpretation in marine soils less than 5m depth – examples from the North Sea, R. Mitchell, S. Wootton, R. Comrie. 2010. 2nd International Symposium
on Cone Penetration Testing, Huntington Beach, CA, Access
Images for Cone Penetration Test
These images are
nigher owned nor hosted by Geotechdata.info. Below are only thumbnail
previews directly linked to the original source of the image. Click on
the image to see it at its original source. You are responsible for
checking the copyright status of images with the owner before using
them.
Where to get Cone Penetration Test services
No corporate member providing this service is available yet.
You provide this service?
Join now
Where to buy Cone Penetration Test equipment
No corporate member providing this equipment is available yet.
You sell this equipment?
Join nowExternal Links
- General description of Cone Penetration Test,The Center for Public Environmental Oversight (CPEO)
- Detailed description of Cone Penetration Test, parameters and sample Logs,J David Rogers, Lecture notes, Advanced Engineering Geology & Geotechnics, Missouri University of Science and Technology
- Cone Penetration Test on Wikipedia
- Simple illustration of description of CPT procedure with photos,R. W. Boulanger, University of California at Davis
- Soil Classification Using the Cone Penetration Test,P. K. Robertson, Canadian Geotechnical Journal, Vol, 27, pp. 152-158, 1990 Link
