Strength of a carbonate silt at the solid-fluid transition and submarine landslide run-out

© 2015 Taylor & Francis Group, London. Submarine landslide run-out is governed by the rheology of the sediment as it evolves from a soil to a viscous fluid. It has been shown previously that the geotechnical characterization of fine-grained sediments can be extended into the liquid range in a continuous fashion (Boukpeti et al. 2012). In this paper, we present the results of strength measurements on a carbonate silt over a wide range of water contents and compare them with results reported previously for two other soils.We then show that a reasonable estimate of submarine slide run-out can be obtained from a simplified analysis based on the energy dissipation through sliding at the base of the slide. Results of the simplified analysis are validated through comparison with run-out predictions obtained using the one-dimensional depth-averaged modelling softwareUWA-SM³. Using a simple formulation to account for water entrainment in the run-out analysis, the influence of the soil rheology on the final run-out is demonstrated. In this case, difference in the rheology of the carbonate silt compared to the non-carbonate fine-grained soils leads to a stronger influence of water entrainment on run-out distance.