Landslides

Teaching Team

  • Olivier Lateltin (Landslides mapping and management) - MODULE RESPONSIBLE
  • Michel Jaboyedoff (Rock Instabilities)-MODULE RESPONSIBLE
randa
claperie
Randa Rockfall (Valais, Switzerland) that occurred in April and May, 1991, representing a total volume of 33 million cubic meter. La Clapière Landslide (Alpes de Haute Provence, France) which has been moving for more than 20 years without blocking the valley of La Tinée, but represents a risk of acceleration.

About the Landslide risk module

General Introduction and Typology of Landslide Phenomena, Case Studies

Landslide processes are reviewed, with a description of their main features. Their classification is presented, according to the classification by Varnes, as well as their possible activity and rate of movement. Their significance on buildings, human life and environment is discussed.

The interpretation of morphological landforms and slope stability indicators is explained, allowing the student to describe the various landslide phenomena.

Instability of Rock Masses

The detection of potential rock instabilities is explained with respect to the presence of various systems of discontinuities that can be monitored and mapped, allowing a kinematic analysis. Limit equilibrium analyses are then performed on rock masses.

Mapping Methodology and Interpretation of Air Photos

The identification of landslides based on the interpretation of air photos is explained, as well as the determination of some features according to the scale of the photographs.The legend to produce landslide phenomena maps is detailed, as well as the standard Swiss representation of landslide hazards.

Landslide Planning and Management of Landslide Hazards

In order to determine landslide hazards, it is necessary to assess the intensity and the probability of a phenomenon. The system of hazard levels in use in Switzerland will be detailed and its application in land planning policy will be presented, as well as other systems in use in neighbour countries. The aspects of landslide risk management (prevention, mitigation) will also be discussed.

Geotechnical Bases and Characteristics

After a brief presentation of the main characteristics allowing the definition of a soil, the parameters related to shear strength, as well as how they can be measured, will be discussed. The basic approaches to assess slope stability conditions will be presented, including the effect of groundwater.

Slope Stability Analysis

The various methods of slope stability analysis will be discussed, with a definition of the factor of safety and of its meaning. Some simple examples will be analyzed.

Monitoring of Landslides

After a presentation of the conditions required to obtain significant monitoring data, the various techniques available to determine surface and underground slope movements, groundwater conditions as well as other parameters will be detailed. The concepts allowing the preparation of a monitoring campaign will be discussed.

Stabilization Measures

After commenting on the classification of stabilization measures, the principles and techniques used in drainage schemes, anchoring programs and mass movements projects will be explained. The stabilizing and protective effects of vegetation will also be discussed, as well as their sustainability and maintenance.

sechillianne
Image1Lafrasse
Sechilienne Rockfall (Isère, France) shows a progressively disaggregating front causing some occasional falls of limited volume. The expected volume liable to fall at a short notice is 3 million cubic meter. General view of La Frasse Landslide (Vaud, Switzerland) that is presented to the CERG students.

Objectives

  • To provide an understanding of the various landslide phenomena, of their causes and of their mechanisms
  • To comment the tools and techniques available for their identification and assessment of their characteristics
  • To present how they can be monitored and modelled
  • To explain the various prevention and protection mitigation actions
  • To develop the hazards and risk they imply
  • To present how they can be taken into account in land planning policy

Associated Field Trips

Visit of a Large Slide

A field trip is organized to the La Frasse Landslide in the Prealps of the Canton of Vaud, near Aigle, where a large permanently active slide experiences occasional crises. This landslide has been extensively investigated and a new hazard mitigation drainage system is about to be built to replace boreholes equipped with pumps.

Field work in the region of les Diablerets (Canton of Vaud)- Landslide and flood combined

The students will be introduced to an area that was affected by a flood in 2005. This area is also susceptible of landslides and debris flows. Participants will proceed to the mapping of the area to assess a multi-hazard and risk considering landslides and floods as well as potentiality of water to carry materials.

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fully2
La Chenaula Landslide, near Lausanne (Vaud, Switzerland) experienced a sudden acceleration in April, 1983, with a total horizontal movement of 8 to 13 m in 3 days. In October, 2000, a major debris flow reached the town of Fully (Valais, Switzerland).

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