A Case-Study of Sustainable Countermeasures against Shallow Landslides in Central Italy

Diana Salciarini,Ludovica Di Pietro,Evelina Volpe,Elisabetta Cattoni

doi:10.3390/geosciences10040130

Abstract

Traditional technical solutions for slope stabilization are generally costly and very impacting on the natural environment and landscape. A possible alternative for improving slope stability is based on the use of naturalistic engineering techniques, characterized by a low impact on the natural environment and being able to preserve the landscape identity and peculiarities. In this work, we present an application of such techniques for slope stabilization along a greenway located in central Italy, characterized by an extraordinary natural environment. First, 22 potentially unstable slopes have been identified and examined; then, among these, two standard type slopes have been selected. For both of them, an appropriate naturalistic engineering work has been proposed and stability analyses have been carried out. These have been performed by considering different piezometric conditions and using two different approaches: (a) a classical deterministic approach, which adopts deterministic values for the mechanical properties of the soils neglecting any uncertainty, and (b) a probabilistic approach that takes into account a statistical variability of the soil property values by means of their probability density functions (PDFs). The geometry of each slope derives from a digital model of the soil with 1 meter resolution, obtained through Light Detection and Ranging (LiDAR) survey provided by the Italian Ministry of the Environment. The soil mechanical characteristics and their PDFs are derived from the geotechnical soil property database of the Perugia Province. Results show an increase in slope stability produced by the adopted countermeasures measured in terms of Factor of Safety ( F s ), Probability of Failure (PoF) and efficiency.

Highlights

In many Italian areas the geological, geomorphological, and hydrographic features lead to a significant landslide susceptibility, mainly caused by intense or persistent rainfalls ([1,2]).The traditional countermeasures adopted to mitigate rainfall-induced landslide risk often produce high impacts on landscape and are typically very costly
Naturalistic engineering is a relatively young discipline including techniques of re-naturalization; anti-erosion and stabilization of shallow covers; and, as defined in [3], it involves the use of all plant species, whether represented by a single plant or a set of plants, considered as any other engineering building material
We present the application of countermeasures based on naturalistic engineering techniques for the stabilization of slopes along a greenway in central Italy

Summary

Introduction

In many Italian areas the geological, geomorphological, and hydrographic features lead to a significant landslide susceptibility, mainly caused by intense or persistent rainfalls ([1,2]).The traditional countermeasures adopted to mitigate rainfall-induced landslide risk often produce high impacts on landscape and are typically very costly. From the geomechanical and stabilization point of view, the most important effect is the mechanical reinforcement exerted by the roots, analyzed by different authors (see, e.g., in [4,5,6,7,8,9]). This consists of an increase in the shear strength of vegetated soil, which is typically included in the Mohr–Coulomb failure criterion as additional soil cohesion ([10,11])

Methods

Results

Conclusion