Field Correlation of Cone and Standard Penetration Tests

In recent years, attempts have been made to correlate standard penetration blow counts with cone penetration tip resistance readings in order to utilize the large data base and experience of standard penetration tests to interpret the results of cone penetration soundings. As part of a liquefaction-susceptibility study on a site consisting of a laterally-extensive hydraulic sand fill over natural sands, correlation data were obtained from side-by-side standard penetration and cone penetration tests. The standard penetration tests were corrected on a standard uniform energy basis and the cone penetration tests were made with an electronic cone. It was concluded that the correlation between the mean grain size of the sand and the ratio of the cone tip resistance to standard penetration test blow counts vary significantly with the presence of fines (material smaller than a US Standard #=200 size sieve). It is suggested that this variation be considered when making evaluations of settlement, stability, and liquefaction analyses for soil profiles explored primarily with a cone penetrometer.