One-dimensional compression creep change under temperature and suction effects

The impact of temperature and unsaturation on the creep behaviour of bentonite is an important topic for environmental geotechnics as in the case of waste storage and energy geostructures. This paper presents an experimental study on the one-dimensional creep of Maghnia bentonite (MB), using two high-pressure oedometer cells, allowing to impose temperature and suction conditions for an unsaturated medium . The characteristics of these two cells and the protocol developed in the framework of this experimental study are briefly presented. The findings highlight a new perspective on the hypothesis (A) which distinguishes between primary and secondary consolidation, and hypothesis (B), which is governed by structural viscosity. The results indicated that the creep behaviour followed the principle of hypothesis (A) under temperature effect, while it followed hypothesis (B) principle under the suction effect. The void ratio variability under secondary compression depends not only on the vertical stress, but also on the temperature and the first load level . Moreover, as soil suction descreases, the normalized void ratio become higher. The creep coefficient (Cae) increased as temperature and vertical stress increased, while they decreased as the suction increased.