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doi:10.2204/iodp.proc.314315316.204.2012

Results

We present a series of tables in the Appendix (Tables AT1, AT2, AT3, AT4, AT5, AT6, AT7, AT8, AT9, AT10) to summarize volumetric flow rate (Q), discharge velocity (v), steady-state head loss (Δhs), steady-state hydraulic gradient (is), hydraulic conductivity (K), and intrinsic permeability (k) from four test runs conducted for each specimen at five levels of effective stress (σ′). Table T2 summarizes the average values of vertical (kv) and horizontal (kh) permeability and the corresponding kh/kv ratio for each specimen.

Figure F6A and F6B shows vertical and horizontal permeability as a function of increasing effective isotropic confining stress. Permeability in each direction shows a generally decreasing trend with effective stress. The most significant reductions in vertical permeability with stress occur for the two relatively shallow samples (25.21 and 129.22 m CSF), as well as for the deeper sample at 214.83 m CSF. The most significant reductions in horizontal permeability occur for the two shallowest samples. In each case, permeability appears to trend toward an asymptote as the highest level of effective stress is approached.

Figure F7 shows the distribution of vertical and horizontal permeability and the corresponding kh/kv ratio with sampling depth. The general trend is for k values to decrease with depth, and the kh/kv ratio is consistently ≥1. Figure F8 shows the kh/kv ratio for all five samples as a function of effective stress. With the exception of samples from 129.22 and 214.83 m CSF at effective stress <0.3 MPa, the kh/kv ratio is near or >1. Consolidation of these two samples tends to increase the anisotropy ratio, whereas consolidation of samples with higher initial anisotropy ratios tends to decrease, or have little effect on, the ratio.

Figure F9 shows how permeability changes with porosity for tests conducted at the highest magnitude of effective confining stress (0.55 MPa). Porosity values are calculated from the posttest measurements of water content (Table T1). The general trend shows that permeability decreases as porosity decreases.

Figure F10 shows rose diagrams with corresponding values for the standard deviation of grain and the index of microfabric orientation calculated using Equations 3 and 4, respectively. These statistics are summarized on Table T3. Figure F11 shows cumulative frequency curves for the grain orientations. These statistics are consistent with random grain orientations. There is no uniform relation between preferred grain alignment and the orientation of imaging surfaces (relative to the core axis) or to the orientation of bedding planes.