Kinematic interaction of a single pile in heterogeneous soil

Abstract

The behaviour of deep foundation under static loads has been widely investigated and the available calculation procedures can be considered suitable for the current engineering applications. However, pile behaviour under seismic loading is more complex and less known, because one can find the contemporary action of inertial forces rising from the over-structure (inertial interaction) and of the soil deformations rising from the seismic waves (kinematic interaction). Italian code DM 14/01/2008 requires the dynamic soil-structure interaction in seismic foundation design to be taken into account, but it does not give any information about kinematic interaction strains evaluation criteria. Experimental evidences and theoretical considerations of many authors show that simply the kinematic interaction may induce high stresses on piles, especially near an alternation between a soft and a rigid soil layer interface. In this work pile behaviour due to kinematic interaction will be examined. An approach based on the differential equation proposed by Kavvadas and Gazetas (Kinematic seismic response and bending of free-head piles in layered soil. Geotechnique, 43, N.2, 207-222, 1993) will be used. The analysis is focused on the response of a single pile in a heterogeneous three-layer soil profile.