Subsurface Exploration using the Standard Penetration Test and the Cone Penetrometer Test


The Standard Penetration Test (SPT) and Cone Penetrometer Test (CPT) have become industry standards for subsurface geotechnical investigations using small diameter (< 8-in. [20-cm]) borings and soundings. Both procedures have evolved over a period of 100 and 70 years, respectively, and have been adopted as ASTM standards. Each procedure has certain advantages over the other, but both can elicit incorrect data under particular subsurface conditions that are often overlooked, depending on the experience of field personnel operating or logging the tests. This paper seeks to explain the operative assumptions employed in both procedures, highlight the various corrections that are commonly employed, and warn the reader of common errors in interpretation. The article concludes by stating that, under most conditions, the joint employment of SPT and CPT together has the greatest potential for characterizing sites correctly.


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Cone penetrometer; Drilling; Site characterization; Site exploration; Standard penetration test; Subsurface exploration; Boring; Geotechnical engineering; Sounding apparatus; borehole logging; cone penetration test; error analysis; error correction; exploration; geotechnical survey

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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© 2006 Association of Environmental and Engineering Geologists (AEG), All rights reserved.

Publication Date

01 May 2006