Ageing of remoulded soils used in geotechnical centrifuge modelling

Centrifuge modelling of geotechnical structures needs to prepare reconstituted soil samples from natural soils. Those models are prepared in containers with volumes ranging from 0.3 to more than 1 m(3) needing a rather large quantity of material. Most often, several successive models must be prepared using and re-using the same soil mass. Two types of soil are used classically in the LCPC centrifuge: sand and clay. After several reuses of sand, one can observe changes in grain size distribution, decrease of the apparent cohesion, and an increase of the friction angle. For clay, one may notice, with reuse, a decrease of liquid limit and plastic limit, similar compression index and swelling index, a decrease of the vertical coefficient of consolidation for low stresses.