Figure 8.
Panel a shows a graph of diffusion coefficient plotted against pre test permeability, with boom clay and synthetic samples following increasing logarithmic trends, with diffusion increasing from about 1.0 into 10 power minus 10 to about 6.5 into 10 power minus 10 as permeability increases from about 1.0 into 10 power minus 19 to about 1.0 into 10 power minus 16. Panel b shows a graph of diffusion coefficient plotted against pre-test intrinsic permeability, with boom clay, eigenbilzen sands, and synthetic samples, where diffusion increases with permeability, with values ranging from about 1.0 into 10 power minus 10 to about 5.0 into 10 power minus 9.(a) Cross-plot of diffusion coefficient against pre-test intrinsic permeability for Boom Clay samples compacted to a pressure equivalent to 400 m depth of burial and synthetic samples comprise of different mineralogical compositions. Note, solid symbols for natural samples represent tests orientated perpendicular to bedding. The graph suggests a fundamental relationship between exists between these two coefficients, with the offset between natural and synthetic samples potentially linked to the compaction pressure of the synthetic sample. (b) Log-log graph including data from the Eigenbilzen Sands