Estimation of driven pile resistance using geostatistical methods

High factors of safety in WSD or low resistance factors in LRFD are often applied to computed pile resistance to take account of the inherent variability in soil properties at a construction site. These factors may be moved closer to unity if dynamic monitoring such as pile driving analysis is performed on representative piles. An alternative or complementary method for reducing the level of uncertainty of pile resistance at a site with variable soil properties is to perform cone penetration tests in the vicinity of the piles to be installed, and the use of geostatistical methods to arrive at a concept has been applied to driven piles at the National Geotechnical Experimentation Site at the University of Houston (NGES-UH), layered clay-sandy silts site. This paper describes the applications of geostatistical methods to cone penetrometer data for predicting driven pile resistance. In this study, three CPT prediction methods, namely those of Schmertmann, Tumay and Fakroo, and LPC; and two alpha methods, namely those of Tomlinson and API, have been used to compute ultimate axial resistance of II identical driven piles installed in overconsolidated clay sites at the NGES-UH. (C) 1998 Elsevier Science Ltd. All rights reserved.