The behaviour of natural and artificial slopes is controlled by their thermo-hydro-mechanical conditions and by soil–vegetation–atmosphere interaction. Porewater pressure changes within a slope related to variable meteorological settings have been shown to be able to induce soil erosion, shrinkage–swelling and cracking, thus leading to an overall decrease of the available soil strength with depth and, ultimately, to a progressive slope collapse. In terms of numerical modelling, the stability analysis of partially saturated slopes is a complex problem and a wide range of approaches from simple limit equilibrium solutions to advanced numerical analyses have been proposed in the literature. The more advanced approaches, although more rigorous, require input data such as the soil water retention curve and the hydraulic conductivity function, which are difficult to obtain in some cases. The quantification of the effects of future climate scenarios represents an additional challenge in forecasting slope–atmosphere interaction processes. This paper presents a review of real and ideal case histories regarding the numerical analysis of natural and artificial slopes subjected to different types of climatic perturbations. The limits and benefits of the different numerical approaches adopted are discussed and some general modelling recommendations are addressed.

The paper studies the seismic behaviour of an existing homogeneous earth dam using a fully coupled finite-element effective stress approach in conjunction with a recently developed multi-surface, elasto-plastic constitutive model for structured soils. The model is calibrated using laboratory test results for the embankment material and the foundation soils. The initial state variables (stress, hardening parameters) are determined by simulating a simplified geological history of the foundation soil, dam construction stages and reservoir impounding, prior to the application of the earthquake shaking at the bedrock level. The paper critically reviews the role of the constitutive model parameters, the hysteretic damping introduced by the model and the additional viscous damping parameters in the accumulation of permanent displacements and in the development and subsequent dissipation of excess pore water pressures due to the seismic loading. The analyses, carried out with reference to a set of earthquake records related to different return periods, show that the overall behaviour of the system in terms of displacements is characterised by a more enhanced deformation pattern of the downstream slope as compared with the upstream one. The large plastic strains accumulation induced throughout the shaking is followed by the development of excess pore water pressures inside the dam and the foundation deposit. Nonetheless, the results are indicative of a satisfactory dynamic performance of the dam, even when subjected to severe seismic loading conditions.

To fully implement seismic performance-based design for geotechnical structures, it is necessary to be able to correctly identify relevant earthquake records for the site in question in conjunction with advanced constitutive models that can accurately predict soil deformation resulting from these dynamic actions. In this paper, a numerical study is conducted to assess the seismic response of an earth dam using different approaches ranging from simple regression models to advanced numerical analyses. A kinematic hardening constitutive model is used to describe the mechanical behavior of the involved clayey soils. Five ground motions are chosen based on an existing hazard assessment to determine the relevant peak ground acceleration and frequency content at the dam site. Two design levels are considered in the evaluation of the seismic response of the earth dam. A comparison in terms of permanent accumulated displacements during the shaking obtained by the different approaches is presented highlighting their limitations and advantages.

Numerical modelling represents a powerful technique to develop a quantitative assessment of the stress–strain mechanisms leading to either first-time slope failures or evolution of slopes already failed in the past. In this perspective, a valid interpretation of the landslide behaviour and an adequate strategy of risk mitigation can be achieved from a numerical validation of both the causative factors and the evolution mechanism that have been previously assumed according to detailed phenomenological or simple analytical approaches. This paper presents two case histories of slow landslides in clay slopes, both located in Puglia (Southern Italy), for which detailed phenomenological studies have been firstly carried out to infer assumptions on the slope failure mechanisms that have been later on verified by means of numerical analyses accounting for soil mechanical behaviour and slope hydraulic processes. The first case study concerns the first-time failure of a stiff clay slope in Lucera, which has been induced by the slow dissipation of negative excess pore water pressures generated by previous quarry excavation at the slope toe. The second case history is represented by the analysis of the stress–strain evolution of the ancient Volturino landslide, which is observed to reactivate mainly in wet seasons.