Abstract
Rainfall-induced landslides are becoming ever more frequent in many regions in the world. Rainfall is one of the most significant triggering factors for slope failures in many regions in the world, particularly in Tunisia. However, due to the high cost of field tests and the difficulty to quantify the infiltration effects in the landslide site, the quantification of rainwater effects still not adequately clarified. Different small-scale models were used to study landslide as a result of change in saturation degree. The physical laboratory model with reduced dimensions has many advantages, like the identification of failure mechanisms, failure initiation and slope movements. The main difficulty of the scale models is to satisfy the rules of similarity. In addition, 1g scale model may not completely represent field condition as soil behavior is different within a natural slope because of stress confinement. The main objective of this study is to determine the optimal dimensions of the slope laboratory model ( small-scale model), using the back analysis approach. Numerical analysis of rainfall test on small-scale slope model is conducted using CODE-BRIGHT software.