Data report: strength characteristics of sediments from IODP Expedition 308, Sites U1322 and U1324: Expedition 308

Abstract

Triaxial strength experiments completed on specimens from Integrated Ocean Drilling Program Expedition 308 Sites U1322 and U1324 document internal friction angles from 17° to 29° and normalized undrained shear strength from 0.21 to 0.36 at maximum shear. Just prior to undrained shearing, lateral stress ratios for these triaxial specimens range from 0.50 to 0.73. In general, internal friction angle and normalized undrained shear strength decrease with increasing vertical consolidation stress. Lateral stress ratio does not vary systematically with vertical consolidation stress. All 18 specimens in this study were collected with the advanced piston corer (APC). Specimens from Site U1322 were from 27.3–72.9 meters below seafloor (mbsf), and those from Site U1324 were from 89.1–304 mbsf. For each specimen we completed a Ko-consolidated undrained triaxial test to provide data on the stress-strain behavior, undrained shear strength, internal friction angle, and secant modulus. Undrained shearing for each specimen was conducted at a vertical consolidation stress exceeding the hydrostatic vertical effective stress for that specimen.