Modeling the stability of terraced slopes: an approach from Valtellina (Northern Italy)

Abstract

This study focuses on the relationships between hydrological processes and the stability of terraced slopes. Emphasis is given to the presence of dry-stone retaining walls and how to explicitly consider them when performing a distributed stability analysis. Valtellina, an Alpine valley of Northern Italy, is selected as study area. In detail, the slope uphill the village of Tresenda, affected by several superficial landslides since 1983, is studied. Dry-stone walls heavily influence the hydrological and geotechnical processes at the slope scale, and it is therefore crucial to consider them when performing a stability analysis on mountainous terraced areas. Walls are usually 0.60-1.00 m wide, and therefore, base maps (Digital Elevation Models and soil depth map) with a horizontal resolution of 1 m have been appositely derived. Working at this horizontal resolution leads to the failure of some basic assumptions of the infinite slope method, usually applied for distributed stability analysis. In this study, we propose an alternative approach based on the global method of equilibrium applied to sections of single terraces one cell wide. A specific sensitivity analysis allowed to fix some constrains to the model, in order to improve the reliability of the results under different mechanical and hydrological conditions. The proposed stability model was calibrated and evaluated on recorded past rainfall events. It resulted to be a good instrument for the identification of the most unstable areas when stressed with high porewater pressure conditions.

The Role of Initial Soil Conditions in Shallow Landslide Triggering: Insights from Physically Based Approaches

“…They generally occur in response to prolonged intense rainfall events and involve either residual weathered soils or transported colluvial deposits. This type of landslides represents a widespread hazard that frequently results in considerable damage to infrastructure and human losses in many mountainous regions of the world, especially in areas characterized by the widespread presence of natural (e.g., [1][2][3]) and/or humanreworked soil cover (e.g., [4][5][6]). For this reason, in recent years great efforts are being made to improve the assessment of the temporal and spatial occurrence of rainfall-induced shallow landslides, especially through physically based models (e.g., [7][8][9][10]).…”

Quantifying the contribution of grapevine roots to soil mechanical reinforcement in an area susceptible to shallow landslides

“…In Northern and Central Italy, these phenomena occurred in the Marche region (Gentili et al, 2006), Langhe (Tiranti and Rabuffetti, 2010), Oltrepò Pavese (Zizioli et al, 2013;Bordoni et al, 2015a), Cinque Terre (Cevasco et al, 2014), Valtellina (Camera et al, 2015), and the Prosecco area. Furthermore, widespread landslides affected cultivated vineyards also in other European countries such as Slovenia (Komac and Ribicic, 2006), Spain (Ramos et al, 2007), Germany (Grunert, 2009) and France (van den Eeckhaut et al, 2010).…”

Relationship between man-made environment and slope stability: the case of 2014 rainfall events in the terraced landscape of the Liguria region (northwestern Italy)

“…Then, land features were statistically tested against landslide crown area with the purpose of pointing out potential relationships between land use and landslides occurrence. In fact, when analysing rainfall-induced landslides in a deeply human-modified landscape, its setting constitutes an important element in determining its hydrological response (Cevasco et al 2014;Camera et al 2015;Galve et al 2015).…”