Etude en centrifugeuse de l'élargissement de remblais sur argile molle

Abstract

This paper presents the results of tests performed on small-scale models of embankments on soft clay foundation. The clay models were prepared from ‘Speswhite’ kaolin powder, which was given an undrained cohesion of 14–18 kPa by consolidation under natural gravity (1g). The main and widening embankments were built in flight inside the centrifuge by using a specifically designed hopper. Seven tests were completed at 70g, with two types of embankment widening. The clay models were equipped with surface settlement, pore water pressure and horizontal displacement gauges. Each test lasted for about 10 h. The geometry of the embankments and the test procedure (preparation of the clay model, instrumentation, loading and measurements) are described in the paper. The results are then analysed and compared with classical analyses for embankments on soft soils. These analyses pointed out the importance of a precise knowledge of the detailed history of the soil models, starting from their preparation in the container under natural gravity. The clay behaviour in the centrifuge depends on a combination of consolidation and creep, which in turn depends on the initial overconsolidation state of the clay. This makes the interpretation of the experimental results more difficult.