Overview of Retrogressive Landslide Risk Analysis in Sensitive Clay Slope

Abstract

Sensitive clays are known for producing retrogressive landslides, also called spread or flowslides. The key characteristics associated with the occurrence of these landslides on a sensitive clay slope must be assessed, and the potential retrogressive distance must be evaluated. Common risk analysis methods include empirical methods for estimating the distance of potential retrogression, analytical limit equilibrium methods, numerical modelling methods using the strength reduction technique, and the integration of a progressive failure mechanism into numerical methods. Methods developed for zoning purposes in Norway and Quebec provide conservative results in most cases, even if they don’t cover the worst cases scenario. A flowslide can be partially analysed using analytical limit equilibrium methods and numerical methods having strength reduction factor tools. Numerical modelling of progressive failure mechanisms using numerical methods can define the critical parameters of spread-type landslides, such as critical unloading and the retrogression distance of the failure. Continuous improvements to the large-deformation numerical modeling approach allow its application to all types of sensitive clay landslides.

Development of a methodology for predicting landslide hazards at a regional scale

“…8) and the present-day slope profile into the Slide software. An analytical slope stability approach (Richer et al 2020) is used in a back analysis (Rocscience 2018). The density (γ) of the clay soil was estimated at 18.6 kN/m 3 from laboratory measurement.…”

“…Multiple sophisticated methods have been developed to evaluate the possibility of landslides in clayed soils and other granular materials. These approaches include analytical and numerical stability analyses using SRF (strength reduction factor) for estimating a single, commonly spherical, failure surface landslide (Richer et al 2020).…”

Development of A Methodology For Predicting Landslide Hazards At A Regional Scale

“…We introduced the 1971 slope geometry (Figure 10) and the present-day slope pro le into the Slide software. An analytical slope stability approach (Richer et al 2020) can undertake a back analysis (Rocscience 2018). To estimate the shear strength parameter of the soil, we undertook several iterations of slope stability modeling using various input values of soil cohesion and analytical methods.…”

Interplay Between Friction and Cohesion: A Spectrum of Retrogressive Slope Failure

“…(2011). In literature, retrogressive slope failures are mostly observed and discussed in relation to the failure of sensitive clay (Carson, 1979; Locat et al., 2011; Mitchell & Markell, 1974; Quinn et al., 2012) or soils which are cohesive with plastic behavior (Chandel et al., 2021; Cuomo et al., 2019; Qi et al., 2018; Richer et al., 2020; Xu et al., 2011). It is also a meaningful topic in submarine landslides and dredging processes (Eke et al., 2011; Puzrin et al., 2017; Van Den Berg et al., 2002; W. Zhang & Puzrin, 2021), and related to substantial tsunamis when occurring at the continental margins (Glimsdal et al., 2016; Løvholt et al., 2015).…”