Tohoku University, Japan

We conducted Atterberg limits measurements, particle size analyses, and uniaxial constant rate of strain consolidation experiments on six sediment samples, which were prepared in the laboratory using resedimentation, to characterize the material and analyze compression and flow behavior. We performed all experiments in the GeoMechanics Laboratory at the University of Texas at Austin (Texas, USA). The six samples are sediment mixtures composed of varying proportions of Nankai silty claystone, which was homogenized from a large number of discrete samples that were collected during Integrated Ocean Drilling Program (IODP) Expedition 322 from Site C0011, and silt-size silica from US Silica. The particle size distributions vary from 56% to 32% clay-size particles with no sand present. The compression index (C (sub c) ) systematically decreases with decreasing clay-size fraction. For clay-rich mixtures, C (sub c) also significantly decreases with vertical effective stress (sigma ' (sub v) ), whereas silt-rich mixtures show constant C (sub c) . Vertical intrinsic permeability decreases with increasing sigma ' (sub v) and varies log-linearly with porosity. Slopes of this log-linear relationship vary between 11.8 and 9.8 for mixtures from 56% clay to 32% clay. At a given porosity, vertical permeability increases by two orders of magnitude for clay contents ranging from 56% to 32%.