The Mississippi River Delta Front (MRDF) is a highly dynamic region prone to submarine landslides. As part of an effort to update geohazard evaluation maps of the MRDF, multicores and piston cores were taken from mudflow gullies, lobes, and undisturbed seafloor during 2014 and 2017 studies. Sediments were collected from the MRDF at Southwest Pass. A comprehensive suite of geotechnical testing on the cores is presented and discussed. The drained shear strength of saturated MRDF samples is determined using torsional ring shear analyses for a range of low effective stresses. The ring shear provides both peak and residual drained friction angles of normally consolidated soils, necessary for accurate slope stability analyses. Empirical correlations developed for shear strength envelopes of subaerial clays for slope stability analyses are compared to measured values from submarine sediments. Stress strain properties are determined using standard triaxial compression experiments under drained and undrained conditions. Photogrammetrically monitored settling column experiment which capture self-weight consolidation results at high temporal resolution are presented. Geotechnical properties are correlated against geological measurements taken from the MRDF at Southwest Pass in duplicate cores. The results of the geotechnical testing suite of these sediments provides a comprehensive view of their resistive strength against mass movements across a dynamic landscape.
Jack A. Cadigan, Navid H. Jafari, Ioannis Y. Georgiou, Samuel J. Bentley, Kehui Xu and Michael D. Miner
Keywords: Submarine Mass Failure, Geohazard, Geotechnical Characterization
Publisher: DFI