Root reinforcement as a measure for shallow landslides risk mitigation

In recent years, the use of vegetation as an intervention for risk mitigation against shallow landslides, as well as for slope erosion control, has begun to spread as a valid alternative to the more traditional methods given the increasingly urgent request for a sustainable design. In fact, reinforcing slopes with roots provides bioengineering solutions that satisfy the principal sustainability criteria for construction better. With reference to risk mitigation, the reinforcement of slopes by means of roots represents a solution that falls within the context of prevention measures, which help to prevent the triggering or reactivation of shallow landslides, allowing for the mitigation of fragility as well as the protection of the natural and anthropic landscape. The soil thickness reinforced with roots shows an increase in soil shear strength due to a two-fold effect: the mechanical effect provided by soil-root interaction and the hydrological effect caused by the evapotranspiration phenomena that yield a reduction in the degree of saturation. The mechanical contribution, in particular, depends on both the tensile strength of the roots and their density and spatial distribution within the soil. The aim of the paper is to show the empirical methodologies that allow evaluating this mechanical contribution to be used in modelling the behaviour of soil reinforced with vegetation.