Rigid pile improvement under vertical cyclic loading: 1g laboratory small-scale modelling

Abstract

This research work is a contribution to the understanding of the behaviour of rigid pile reinforcement under a quasi-static vertical cyclic loading. While the system behaviour under static loading is well known, the response of this technique under cyclic and/or dynamic loading is not yet fully understood and cannot be predicted. This work first consists in performing a series of tests on an instrumented small-scale laboratory model, with a scale factor of 1/10 on the lengths. A digital image correlation method is implemented to study the displacement field inside the load transfer platform (LTP). The parametric study performed with the physical model gives an insight on the influence of LTP's thickness and on the presence of a rigid slab at its surface on the behaviour under cyclic loading: a settlement accumulation during the cycles is obtained in all the studied cases; the settlements' accumulation is less for a smaller LTP thickness; and the presence of the rigid slab increases the settlements' accumulation. Nonetheless, its presence results in a reduction of the total settlement during a further monotonic loading. In a second step, the experimental results will serve as a database for the validation of a 3D numerical model.