Effects of Anisotropy of Preferential flow on the Hydrology and Stability of Landslides

Infiltration is one of the most important landslides triggering mechanisms and it is controlled by the hydraulic characteristics of the soil, which depend on degree of saturation, existence of preferential flow paths and anisotropy. In order to account for preferential flow that can have place in macro-pores and fissures, it is common to represent the soil matrix by means of the superimposition of two different domains: a soil matrix domain, which mainly accounts for the flow in the porous matrix, and preferential flow domain representing the flow through macro-pores and fissures. There have been recent investigations on the influences of preferential flow on slope stability; however, the combined effects of anisotropy and preferential flow on infiltration processes and on rainfall induced landslide mechanisms have not been studied yet, at our knowledge. Aiming at better understanding the effects that anisotropy combined with preferential flow has on the infiltration process, we investigated the stability of a hillslope using a numerical modelling approach. Results indicate that anisotropy affects the slope stability and its failure area.