Gas Breakthrough of Compacted Bentonite/Sand-Argillite Interfaces
This paper focuses on gas breakthrough tests through bentonite-argillite interface. The main contribution of our study is to provide insights into the swelling kinetics, gas breakthrough pressure of these materials. During the tests, bentonite/sand plugs and bentonite-argillite plugs are used to perform swelling tests and gas breakthrough tests. Experimental results show that continuous gas passage through fully saturated bentonite/sand is not obtained until 10.5 MPa gas pressure. When a bentonite/sand plug swells inside a smooth metal tube, gas passage occurs at 7–8 MPa, which is similar to the effective swelling pressure of bentonite, as measured by independent swelling experiments. For argillite alone, saturated with water until sealing (water permeability on the order of 10−20–10−21 m2), gas breakthrough may occur at as low a pressure as 0.2 MPa and up to 6 MPa for undisturbed argillite. Finally, also after full water saturation, continuous gas breakthrough through the bentonite-argillite interface is detected at between 7 to 8 MPa gas pressure. It is interpreted that the argillite rock or the bentonite-argillite interface are both preferential pathways for gas migration when all materials become fully saturated.
KeywordsSwelling clay Bentonite-sand plug Argillite Bentonite/argillite interface Gas breakthrough
The authors are grateful for the support provided by the Open Fund (KLE-TJGE-B1703) of Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education (Tongji University), the Natural Science Foundation of Jiangsu Province of China (BK20160249) and the Fundamental Research Funds for the Central Universities (China University of Mining and Technology) (2017QNA29).
- Alonso EE, Olivella S, Arnedo D (2006) Mechanisms of gas transport in clay barriers. J Iber Geol 32(2):175–196Google Scholar
- Bosgiraud J (2004) Scope of work design, fabrication, assembly, handling and packaging of buffer rings. Technical report C CC ASTE 04-0520/B, ANDRAGoogle Scholar
- Gatabin C (2005) Selection and THM characterization of the buffer material. Technical report RT DPC/SCCME 05-704-B, ANDRAGoogle Scholar
- M’Jahad S (2012) Impact de la fissuration sur les propriétés de rétention d`eau et de transport des géométraux. Application au stockage profond des dechets radioactifs. PhD thesis, Ecole Centrale de Lille, France (in French)Google Scholar
- Pusch R, Forsberg, T (1983) Gas migration through bentonite clay. Technical report TR. 83-71. SKBF-KBS, SKBF-KBS technical reportGoogle Scholar