A methodology for evaluating liquefaction susceptibility in shallow sandy slopes

The paper illustrates a modeling approach for evaluating the liquefaction susceptibility of shallow sandy slopes. The proposed methodology consists of two main components: (i) a theoretical framework for undrained stability and (ii) the MIT-S1 constitutive model for simulating the response of sands. In the first part of the paper, the use of a stability index able to capture the onset of undrained failure in infinite slopes is illustrated. In the second part, the practical significance of the method is discussed by back-analyzing the series of flow failures in an underwater berm at the Nerlerk site. The reinterpretation of these events in the light of the theory of material stability confirmed that liquefaction was a plausible mechanism for the failures. In addition, the analyses have provided a prediction of the spatial distribution of the unstable masses which is compatible with what was observed through bathimetric surveys conducted after the events. This particular application of the theory supports the idea that realistic constitutive modeling is crucial for achieving consistent predictions of liquefaction potential under field conditions.