City Research Online

Abstract

During construction of rotary bored piles it is necessary to install a temporary casing to prevent the collapse of material into the open bore and provide edge protection. T he preferred method of removal for some contractors is by means of the handling crane. The Federation of Piling Specialists (2010) released guidance to predict the load developed in the removal of casings. This paper investigated whether the recommended constants applied to the overburden and clay terms were reasonable for various casing diameter s , embedment and depth of overburden. A series of five ce ntrifuge tests were conducted where loads were recorded as casings were extracted. Results showed that the FPS method over predicted the pull - out force and indicated that the adhesion factor, α , and angle of dilation between the casing and soil, tan δ , are not constant. This paper proposes a new method of predicting extraction forces which was found to predict forces to within ±10% of those measured in centrifuge tests.

Publication Type:	Article
Additional Information:	Copyright © ICE Publishing. This is an accepted manuscript of an article published by ICE Publishing in Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, available on line: https://www.icevirtuallibrary.com/doi/10.1680/jgeen.17.00134
Publisher Keywords:	Models (physical), piles & piling, safety & hazards
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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