Disconnected piled raft in Gothenburg clay - A feasibility study of disconnected piled raft in large depth of clay

Abstract

Disconnected piled raft is a rather new foundation method, where piles work as an soil reinforcement instead of supporting the raft directly. The benefit of this method is that horizontal forces subjecting the soil, will not break or buckle the piles. The disconnected piled raft method has been performed on large scale projects and this thesis is done to test the feasibility in Gothenburg clay conditions. A numerical model in the software PLAXIS were made where different heights of the cushion were tested along with different parameters for the materials. In the results it showed that a cushion thickness the same height as the width of the pile were superior in terms of displacements. Determination of the spacing were also done with previously mentioned cushion thickness as well as the time depending consolidation analysis. A sensitivity analysis of the material were made to investigate which of the parameters did affect the displacements the most. Conclusion of this thesis were that the disconnected piled raft method is feasible for the Gothenburg clay conditions if certain criterion is meet.