Effects of shear band propagation on submarine landslide

Interbedded layers of glacial deposits and marine or glacimarine clay layers are a common feature of offshore sediment. Typically, offshore marine clays are lightly overconsolidated sensitive clay. Some case histories on submarine landslides show that the slip surface passes through these marine clay layers. In this paper a model is proposed for post-peak strain softening behavior of marine sensitive clay. The slope failure mechanism is examined using the concept of shear band propagation. It is shown that shear band propagation and post-peak stress-strain behavior of clay layers are two major factors in submarine slope stability analysis. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).

Modeling of soft clays response for seismic triggering of submarine slides

Submarine landslides pose considerable hazards to coastal communities and offshore structures. The difficulty and cost of obtaining undisturbed samples of offshore soils for determining material properties required for slope stability analyses contribute to the complexity of the problem. There are significant advantages in using a simplified model for the seismic response of submarine slopes, compatible with the limited amount of information that can be realistically gathered, but still able to capture the key elements of clay behavior. This paper illustrates the process of parameter determination and calibration of the SIMPLE DSS model, developed for the study of seismic triggering of submarine slope instabilities. The selection of parameters and predictions of monotonic and cyclic simple shear response are carried out for Boston Blue Clay, a marine clay extensively studied and with a large experimental database available in the literature. The results show that the simplified model is able to reproduce the important trends in the response of the soil, especially in accounting for the effect of the slope.