Christophe Bonnard

Bio: Christophe Bonnard is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Landslide & Natural hazard. The author has an hindex of 9, co-authored 18 publications receiving 1617 citations.

Landslide risk management in Switzerland

Abstract: Six percent of Switzerland is prone to slope instability. New federal regulations require regional authorities (cantons) to generate natural hazard maps and the zoning of mass movements in order to restrict development on hazard-prone land. The Codes of Practice for hazard maps use red, blue and yellow respectively, to indicate areas of prohibited construction, construction with safety requirements and construction without restriction. They need considerable efforts to ensure communication with local populations. The present state of landslide hazard mapping in the 26 cantons, the transcription of hazard maps to local management plans and the corresponding rules are presented.

Landslide hazard and risk zoning for urban planning and development

Abstract: Note: Sols Reference LMS-CONF-2005-003 Record created on 2006-11-09, modified on 2016-08-08

Modelling the behaviour of a large landslide with respect to hydrogeological and geomechanical parameter heterogeneity

Abstract: Thanks to a sophisticated transient hydrogeological modelling allowing the determination of the pore pressure fields in La Frasse landslide mass during a crisis, it has been possible to model the mechanical behaviour of the slide and obtain results that prove to be similar to the monitored data, in terms of peak velocity, distribution of velocity with time and space and total displacements. Such results are reached only when appropriate constitutive modelling laws are used, and when geotechnical tests supply all the required parameters. The main results concern the potential effect of a drainage system during a crisis, like the one experienced in 1994. It can include vertical boreholes equipped with pumps or drains drilled from a gallery. The draining system reduces horizontal displacements down to 5% of the values modelled during the crisis. This effect, which appears to extend over a large width, will be even more significant if the boreholes discharge the drained water into the gallery, due to its extension in the presently stabilised landslide mass below the active zone. The modelling tools developed for La Frasse landslide thus provide all the necessary information to optimise the drainage scheme.

The Varnes classification of landslide types, an update

Abstract: The goal of this article is to revise several aspects of the well-known classification of landslides, developed by Varnes (1978). The primary recommendation is to modify the definition of landslide-forming materials, to provide compatibility with accepted geotechnical and geological terminology of rocks and soils. Other, less important modifications of the classification system are suggested, resulting from recent developments of the landslide science. The modified Varnes classification of landslides has 32 landslide types, each of which is backed by a formal definition. The definitions should facilitate backward compatibility of the system as well as possible translation to other languages. Complex landslides are not included as a separate category type, but composite types can be constructed by the user of the classification by combining two or more type names, if advantageous.