Experimental Study on Swelling Property and Gas Flow in a Compacted Bentonite-Sand Sample
This paper focuses on the experimental research on swelling properties gas migration in a compacted bentonite-sand plug. The aim is to investigate the swelling behaviour, gas breakthrough pressure as well as its sealing efficiency. Results show that bentonite-sand swelling is incomplete from 4 MPa gas pressure, so that gas breakthrough occurs at very low pressures (on the order of 1 MPa). Gas permeability of the bentonite-sand plug is affected by the variation in the confining pressure, so that tightness to gas can be achieved at a certain coupled hydro-mechanical condition. Specially, when the confining pressure is equal to 7 MPa and the water saturation degree is 86–91%, gas permeability can decrease to 10−20 m2.
KeywordsHigh-level radioactive waste Bentonite Gas permeability
The authors are grateful to the financial support from the Fundamental Research Funds for the Central Universities (Grant No. 2018ZZCX04).
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