Experimental research on water retention and gas permeability of compacted bentonite/sand mixtures - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Soils and Foundations Année : 2014

Experimental research on water retention and gas permeability of compacted bentonite/sand mixtures

Résumé

Highly compacted bentonite-based materials are often considered as buffer or sealing materials for deep high-level radioactive waste repositories. In situ, the initial state of bentonite-based materials is only partially saturated, which has a very high suction that will promote water absorption from the host rock. In addition, a gradient of water saturation will be formed between the external part and the central part of the compacted bentonite blocks. In this paper, water retention tests, under both constant-volume and free-swelling conditions, were performed to investigate the suction behavior of a compacted bentonite/sand mixture. In order to investigate the sealing ability of the partially saturated bentonite/sand mixture, gas permeability tests were also carried out under the in situ confining stress. It was found that the confining conditions have a limited effect on the water retention capacity of the compacted bentonite/sand mixture at lower levels of relative humidity (RH), while this influence is significant at higher RH levels. The results of gas permeability tests show that gas permeability is very sensitive to the water content and the confining pressure. When the sample (stable at RH=98%) was subjected to a in situ confining pressure (7–8 MPa), the gas permeability was very low (1.83×10–14 m/s) which indicates that gas tightness can be obtained even though the sample is not fully saturated.

Dates et versions

hal-01093159 , version 1 (10-12-2014)

Identifiants

Citer

Jiangfeng Liu, Frédéric Skoczylas, Jian Liu. Experimental research on water retention and gas permeability of compacted bentonite/sand mixtures. Soils and Foundations, 2014, 54 (5), pp.1027-1038. ⟨10.1016/j.sandf.2014.09.011⟩. ⟨hal-01093159⟩

Collections

CNRS
43 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More