Abstract
This paper introduces a surface layer method for the analysis of slope stability using finite elements. When stability of a slope is calculated using the strength reduction method, the slope typically fails at local surface irregularities, which leads to numerical divergence that stops the calculation.
It is then impossible to quantify the factor of safety for potentially dangerous landslides of larger dimensions. In this paper, a method is introduced in which a weightless elastic surface layer is applied at the surface, which aims to stabilize the surface of a numerical model during the strength reduction.
A vertical cut through the surface layer then predefines the surface contour of the landslide, while the shape and depth of the slip surface along with the associated factor of safety is the output of the analysis. A typical use-case scenario is when the landslide shape is known a-priori (for example when analysing existing landslides).
If it is not known, various landslide shapes can be tested by searching for an outline with the lowest factor of safety. This is similar to the limit equilibrium method, where a complete slip surface including its surface trace must be predefined.
The proposed method was validated using parametric studies both in 2D and 3D; its importance is most pronounced in 3D where the surface morphology is highly complex. Practical application of this method is demonstrated by the back analysis of the Dobkovi & ccaron;ky landslide, which occurred in 2013 during construction of the highway D8 in Czech Republic.