ABSTRACT
Important economic resources are annually lost in Algeria to face damages due to landslides. Geological and climatic condition, sometimes coupled with human activities give a great contribute landslides triggering. The National Road RN 75 in the Setif’s Wilaya is a particular example of natural hazards that require risk management. In a sensitive area, climatic effects (due to snow and thawing cycles) and earthworks necessary to change the road alignment in correspondence of the reservoir of Mahouane dam, resulted in a large slope deformation (a few meters) with a slip surface up to 20 m deep, completely destroying the new road. In such situations and since poor financial resources were available for investigations, we adopt fast methods to analyze large areas, as for example by means of portable aero-photogrammetric equipment, which turned out to be very useful. The paper shows the strengthening interventions that we have planned to ensure safety condition.
