Numerical model of a piled foundation with respect to the stress history

Piled foundations are used to increase the bearing behaviour of foundations. In contrary to a plain foundation both the settlements are reduced and the stability is increased for the combined system. Usually the system is either foreseen in the planning state or in case of under pinnings the piles may be installed subsequent in a certain loading state. Both cases are studied in this paper. Using the FEM parameter studies are performed. In our model the underground consists of a dense sand. The material behaviour of the soil is described by a plastic law. In order to show the effect of soil memory in different stress-strain states the piles are installed at different foundation settlements. The central point of this paper is the improvement of the settlement behaviour by the combined system. This effect is demonstrated at a simplified system existing of a circular foundation as well as a pile in the centre line. The pile length is varied.