Negative skin friction on piles: a simplified analysis and prediction procedure

Abstract

In order to describe the interaction between a single pile and a consolidating soil a stress transfer approach at the interface is proposed. The non-linear, plastic character of the shear stress acting on the pile shaft and the adequate modelling of unloading and cyclic behaviour are properly incorporated through a ‘shooting’ solution procedure of the equilibrium equations. The whole problem is formulated in dimensionless terms both for external uniform loading conditions and for changes in piezometric levels. The formulation and the computational procedure developed are fairly general and may accommodate arbitrary layering and complicated loading sequences. In many practical situations the whole length of the shaft-soil interface has reached a limiting shear stress state except for a narrow zone around the neutral point. It is then possible to derive analytical solutions for the main design parameters. Their usefulness has been checked through several well-documented case records.