Workreport 2012-100



Downscaled Tests on Buffer Behaviour


Pintado, X., Adesola, F. & Turtiainen, M.



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Two types of tests, nicknamed X-Boy (bentonite sample diameter 350 mm, sample height 800 mm) and Transu (sample diameter 269 mm, sample height 800 mm), were performed to investigate the early saturation behavior of the buffer at mock-up scale using distinct point inflows at 0.1 L/min across a range of solution salinity from tap water to 35 g/L. Specifically, swelling pressure development, piping and erosion due to groundwater inflow and the extent of the homogenization process from the initial heterogeneous state (i.e., compacted blocks and either an empty or pellet-filled gap between the blocks and test device wall) were followed.

For all test formats a set of consistent observations were made. No significant resistance to inlet water pressure was observed for any of the tests, due to developments occurring within the test cylinders, indicating that flow pathways through the buffer system remained open. Effluent solids concentrations above background levels were observed over the course of all of the tests indicating continuous erosion. Relatively low swelling pressures (both axial and radial) were observed during all of the tests. Non-uniform, radial swelling pressure development and saturation (from post-mortem sampling) were observed for all of the tests.


Buffer, erosion, homogenization, saturation, swelling pressure.


Downscaled Tests on Buffer Behaviour (pdf) (11.9 MB)


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