ISSN: 1945-7545
CODEN: GTJODJ
Page Count: 9

An Improved Statistically Based Technique for Evaluating the CPT Friction Ratio

Jaksa, MB
Senior lecturer, Adelaide University,

Kaggwa, WS
Senior lecturer, Adelaide University,

Brooker, PI
Senior lecturer, Adelaide University,

(Received 27 January 2000; accepted 4 June 2001)

Abstract

This paper examines a statistical technique known as the cross-correlation function (CCF) for determining the shift distance associated with the cone penetration test (CPT). When evaluating the friction ratio, FR ( = fr/qc), for soil classification purposes, it is essential that the measured values of ), for soil classification purposes, it is essential that the measured values of qc and fs are shifted relative to one another because of the physical offset between the cone and the friction sleeve. Generally, the shift distance is estimated by means of empirical and subjective methods, a value of 75 to 100 mm is adopted, or it is ignored all together. Using a series of case studies, this paper demonstrates that the CCF is a useful and objective technique for estimating the shift distance. In addition, a phenomenon associated with sleeve friction measurements related to elastic rebound of clay soils is discussed.

Keywords:
cone penetration test, friction ratio, cross-correlation function, soil classification, soil profiling, elastic rebound

Paper ID: GTJ11080J
DOI: 10.1520/GTJ11080J
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