Comparison of frustum confining vessel (FCV) and full-scale testing for helical and expanded piles geotechnical performance

Abstract

This study focuses on investigating the compression and pullout load-displacement characteristics of various pile types using a frustum confining vessel at Amirkabir University of Technology (FCV-AUT) and full-scale tests. The FCV-AUT provides a versatile platform for physically modeling reduced-scale deep foundations in a laboratory setting, accounting for flexible geometric and stress factors, and the full-scale load tests took place at two research sites situated along the southern coastline of the Caspian Sea. A comprehensive dataset comprising 40 model-scale and 15 full-scale load tests on different pile configurations (including conventional, helical, and expanded piles) installed in sands has been compiled to facilitate a geotechnical performance evaluation. Conventional piles, encompassing cast-in-place drilled shafts, H piles, pipe piles, and box piles, were considered in the analysis. Helical piles with one to three helixes and various expanded piles, including self-expanded, bubble, and wing piles, were also examined. Notably, among the tested piles, those installed through jacking and expanded piles displayed the highest resistance to compression. Conversely, helical piles and expanded piles demonstrated superior pullout performance when compared to conventional piles. Comparisons between physical model-scale tests and full-scale tests validate the suitability of FCV-AUT for assessing the geotechnical performance of diverse pile types in sand under realistic stress conditions.