Tapering Effects on the Installation of Suction Caissons in Clay

Abstract

This paper reports results from an investigation on the tapering effects on the installation and pull-out performance of suction caissons. A numerical finite element approach has been used for the study. The finite element models have first been calibrated/verified against several available experimental data for the installation of the upright suction caissons in clay. The verified models have then been used to examine the behaviour of the tapered suction caissons during the pull-out and installation phases. Numerical results indicate that tapered caissons present considerable enhancement in their pull-out capacity comparing to those from corresponding upright caissons. Also it has been noticed that in general tapered caissons of positive wall slopes need extra forces, in comparison to their equivalent upright caissons, to achieve a full penetration. However, at least with those models studied, these extra forces have found to be less than twenty five percent when the wall slope varies from zero (upright) to 15%. This is while the additional pull-out capacities that might be achieved from these tapered suction caissons could reach to several hundred percents. An almost linear relationship has been observed between the total installation force and the caisson’s wall slope.

Model testing of upright and tapered suction caissons in sand

“…has already been investigated by a number of researchers (Bang et al 2000;Cassidy et al 2006;Narasimha Rao et al 2006;Zeinoddini et al 2010). Some previous numerical investigations indicated that positively tapered suction caissons may provide pull-out capacities considerably higher than that of their equivalent upright caissons Zeinoddini et al 2008a;Zeinoddini et al 2008b;Zeinoddini, Hobbi, et al 2009;Zeinoddini, Keyvani, et al 2009). A thorough evaluation of the performance of tapered suction caissons requires further studies, particularly, experimental investigations.…”