International Symposium on Frontiers in Offshore Geotechnics, (DFI)
Ultimate Capacity of Short Piles in Clay under Lateral Loading
Chris M. Martin, Harvey J. Burd, Ross A. McAdam, Peter J. Houlston and Isabel von Celsing
Computational limit analysis is used to study the lateral capacity of a short circular pile (or suction caisson) in undrained clay. Attention is confined to non-rotating (i.e. fixed-head) piles. The analyses are performed using 3D finite element limit analysis. The clay is idealized as a rigid-plastic material obeying the von Mises yield criterion. The parameters of interest include the aspect ratio of the pile (L/D), the pile/soil interface properties (adhesion factor /spl alpha/ and tension capacity T), and the normalized unit weight to strength ratio of the clay (/spl gamma/D/s/sub u/). For each combination of parameters, several iterations of adaptive remeshing are used to obtain lower and upper bounds that bracket the exact plastic collapse load. The analyses also provide insights into the variation of the unit lateral resistance factor (N/sub p/) with depth, as well as revealing details of the 3D soil failure mechanisms. The N/sub p/ profiles are relevant to the development of theoretically sound soil reaction curves for Winkler-type soil-structure interaction analyses of short piles under lateral loading. The plasticity solutions obtained from the 3D finite element limit analyses are compared with results from the influential paper by Murff and Hamilton (1993), where upper bound limit loads were computed by optimizing a composite wedge and flow-round failure mechanism.
|article #3565; publication #1069 (IC-ISFOG21)|