Benchmark of experimental techniques for measuring and controlling suction

The paper presents a benchmarking study carried out within the MUSE network aimed at comparing different techniques for measurement and control of suction. Techniques tested by the eight MUSE research teams include axis-translation (pressure plate and suction-controlled oedometer), high-capacity tensiometer, and osmotic technique. The soil used in the exercise was a mixture of uniform sand, sodium bentonite (active clay), and kaolinite (non-active clay), which were all commercially available. Samples were prepared by one team and distributed to all other teams. They were normally consolidated from slurry under one-dimensional conditions (consolidometer) to a given vertical stress. The water retention characteristics of the initially saturated specimens were investigated along the main drying path. Specimens were de-saturated by applying suction through the liquid phase when using axis translation technique or osmotic method and de-saturated by air-drying when suction was measured using
high-capacity tensiometers. In general, the same technique was tested by at least two teams. The water retention curves obtained using the different techniques are compared and discrepancies are discussed in the paper.