Numerical Analysis of the Drilled Horizontal Drains Efficiency in Physical Slope Model: The Role of the Soil Water Retention Property

Rainfall leading to a variation of the groundwater regime has been considered as a main factor that caused slope failures in many regions in the world, particularly in Tunisia, where roads were recently well damaged under intensive precipitations. The installation of drilled horizontal drain can be an improvement alternative technique which affects the flow path, reduces the pressure in the soil by reducing the groundwater location. This study examines the effectiveness of drilled horizontal drains to stabilize the residual slope in a physical model. This is conducted in relation to the water retention property of the soil. So, in this study, different types of soils characterized by their corresponding water retention curves were considered. Using the proposal model implemented in CODE-BRIGHT software, we discuss many of the issues of the drain’s efficiency basing on the water pressure and the displacement field changes. The paper discusses also the role of the main parameters which characterize the water-retention of the soil, such volumetric water content at saturation and air-entry suction.