Experimental and numerical studies on pile groups under cyclic lateral loading

The behaviour of soils, both fine- and coarse grained, under cyclic loading is complex. Cyclic lateral loads on piles in sand for example lead to either a densification or a loosening of the surrounding soil. However, the design of pile foundations under cyclic loading is still usually based on modifications to the more simplistic monotonic loading conditions. As part of a research project to develop a framework for quantifying cyclic effects on pile groups, centrifuge model tests on single piles and pile groups in dry silica sand have been carried out at the Centre for Offshore Foundation Systems (COFS) in Perth, Australia. In the scope of this paper, the results of the centrifuge tests are briefly discussed and compared to numerical simulations with the finite element method, which have been carried out to back-analyze selected tests. In the numerical analysis, a hypoplastic soil model with the intergranular strain extension has been applied to capture the behaviour of sand under cyclic loading.