- Title
- Effects of stress and suction on the volume change behaviour of GMZ bentonite during heating
- Creator
- Ye, Wei-Min; Wang, Qiong; Zhang, Ya-Wei; Chen, Bao; Chen, Yong-Gui
- Relation
- 12th International IAEG Congress (IAEG 2014). Proceedings of the 12th International IAEG Congress [presented in Engineering Geology for Society and Territory, Vol. 6] (Torino, Italy 15-19 September, 2014) p. 541-543
- Publisher Link
- http://dx.doi.org/10.1007/978-3-319-09060-3_97
- Publisher
- Springer
- Resource Type
- conference paper
- Date
- 2015
- Description
- Unsaturated compacted bentonite is considered by several countries as sealing/backfill material in the deep geological repository for high-level radioactive waste (HLW). In the field conditions, where bentonite is subjected to coupled thermo-hydro-mechanical actions, its thermo-mechanical behavior may change with suction and stress variations. This work focuses on the compacted Gaomiaozi (GMZ) bentonite, which has been chosen as potential sealing/backfill material in the Chinese repository concept. The effects of vertical stress and suction on the volume change behaviour during thermal loading (heating) were experimentally investigated. A high pressure oedometer frame permitting simultaneous control of temperature, suction and pressure was used for testing. Compacted samples were heated from the original temperature of 20 to 80 °C at total suctions ranging from 4.2 to 110 MPa, and vertical stress of 0.1 or 5 MPa. Results show that heating at constant suction and vertical stress induces either swelling or contraction. At a constant vertical stress, samples with higher suctions swell during heating, and the lower the suction the lower the swelling strain; on the contrary heating resulted in a thermal contraction with lower suctions. At a constant higher suction (110 MPa), sample swells during heating; however, for a relative lower suction, a contraction was induced by heating for a higher vertical stress of 5 MPa. In short, at high pressure and low suction, heating tends to induce contraction, while at low pressure and high suction, heating induced expansion.
- Subject
- GMZ bentonite; suction; vertical stress; heating; volume change
- Identifier
- http://hdl.handle.net/1959.13/1331290
- Identifier
- uon:26591
- Identifier
- ISBN:9783319090597
- Language
- eng
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