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A programme of 20 centrifuge tests was carried out on piled embankments without reinforcement to assess the influence of geometric parameters on surface settlement and on the load transfer mechanism. The three main geometric parameters studied were pile spacing, embankment height and area ratio, which were varied in ranges commonly adopted in practice. The measurements of the forces on the piles allowed assessment of the load transfer mechanisms, and thus the efficiency, which were shown to increase with embankment height and area ratio. Subsoil stress between piles was also assessed and compared with literature data. The centrifuge model test results for stress on the subsoil at the point of ‘maximum arching’ presented good agreement with the method proposed by Hewlett and Randolph in 1988. Measurements of the surface settlements allowed evaluation of the critical height at which surface differential settlements did not occur. The values of critical height obtained herein are in good agreement with recent literature recommendations.

A 50-mm-diameter circular aluminium tube was instrumented with two optical fibres that consist of 13 Fibre Bragg Grating sensors (FBGS) for each. The performance of the FBGS was evaluated by applying a series of increasing transversal loads at 1×g level and comparing the strains measured by FBGS with those calculated from the Euler-Bernoulli beam theory. Centrifuge test was then conducted at 100×g to estimate the transversal response of the calibrated model pile that had been jacked 450 mm into saturated sand and horizontally loaded at 500 mm above the ground. The profiles of the normal strain, bending moment, soil reaction and pile deflection were measured or determined, allowing to construct the soil reaction-pile deflection (P-y) curves. The results confirmed the reliability of the FBGS at 100×g by giving satisfactory measurements on bending moments and coherent measurements on shear force at the ground level.