53 / 2019-06-02 17:52:51

Estimating initial failure surface depths and volumes based on surface information

Landslides, failure surfaces, volumes, depths

水库地质灾害防治与生态环境保护 > 地质灾害防治技术

Jaboyedoff M.1, Carrea D. 1, Derron M-H. 1, Fei, L. 1, Oppikofer T. 2, Penna I.M. 3, Rudaz B.1
1Risk-group - ISTE - Institute of Earth Sciences, University of Lausanne, Geopolis 3793 CH-1015 Lausanne, Switzerland
2Terrranum, Rue de l'Industrie 35, 1030 Bussigny, Switzerland
3Geological Survey of Norway, Leiv Eirikssons vei 39, 7491 Trondheim, Norway
Here we propose to review the methods developed to define initial landslide failure surfaces and volumes based on surface information. It starts with the simplest models, such as volume estimation based on ellipsoids, or information that can be deduced from surface displacement or morphology. A simple method to define the volume of a rockslide is also proposed. Based on a digital elevation model (DEM) the sloping local base level (SLBL) allows to obtain by an iterative calculation solution for possible failure surfaces. The balanced cross section methods provide the depth of the failure surface are illustrated. Based on predefined assumptions, stating that vectors of displacements are parallel to the failure surface, allow to obtain a solution for the failure surface either along translational or circular landslides. This method can be complexified by adding a mass balance equation. Recent works demonstrated that using an inverse model, a mass balance equation and assumptions about the rheology provide a solution for the failure surface.
A set of examples illustrates these methods. It shows that if several methods can be applied to the same landslide and if the results are coherent, it gives a certain confidence to the results. The advantages and disadvantages of the methods are discussed. It shows that future developments based on computer models will certainly provide new tools to obtain failure surfaces solutions rather accurately without subsurface investigations including uncertainty. This will possible only by taking advantage of high-resolution topography and interpretations of the morphology.