The Geo-Hydro-Mechanical Properties of a Turbiditic Formation as Internal Factors of Slope Failure Processes

Nunzio Losacco,Osvaldo Bottiglieri,Claudia Vitone,Francesca Santaloia,Federica Cotecchia

doi:10.3390/geosciences11100429

Nunzio Losacco, Osvaldo Bottiglieri + Show 3 more

Open Access

https://doi.org/10.3390/geosciences11100429

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Abstract

Similar to many inner areas of Southern Europe, the Daunia Apennines are affected by widespread landsliding, often consisting of slow, deep-seated movements. Recurrent acceleration of these landslides causes damage to buildings and infrastructures, severely biasing the socio-economic development of the region. Most landslides in the area of study occur within clayey units of turbiditic flysch formations, often severely disturbed by tectonic thrust and previous landsliding. The Faeto Flysch (FAE) is one of the most widespread turbiditic formations in the Daunia Apennines and is representative of the tectonised geological formations involved in slope failure. This work, by examining the landslide processes occurring at four pilot sites, aims at connecting the observed mechanisms to the geo-hydro-mechanical setup of FAE in the slopes. It is found that the soil portion of FAE consists of highly plastic clays, resulting in low intrinsic shear strength, and hence controls the initiation and progression of failure in the slopes, as such representing an internal predisposing factor to landsliding. In addition, the presence of fractured rock strata confers a high permeability at the slope scale, with respect to that of the soil matrix. This results in severe piezometric levels in the slope, which represent another internal predisposing factor to failure, and in the ability to induce significant seasonal pore water pressure oscillations down to great depths, connected to rainfall infiltration, thus triggering the recurrent acceleration of the landslides.

Highlights

The eastern front of the Italian Southern Apennines, i.e., the Daunia Apennines, is a location of extensive slope failure processes
Similar to many inner areas of Southern Europe, the Daunia Apennines are affected by widespread landsliding, often consisting of slow, deep-seated movements
Most landslides in the area of study occur within clayey units of turbiditic flysch formations, often severely disturbed by tectonic thrust and previous landsliding

Summary

Introduction

The eastern front of the Italian Southern Apennines, i.e., the Daunia Apennines, is a location of extensive slope failure processes. As discussed by [2], most of the landslides in the Daunia Apennines occur within clayey units that are part of flysch formations, of turbiditic origin, consisting of limestone and sandstone strata interbedded with clayey marls and clays, which often represent the matrix of the formation These materials are heavily disturbed due to both tectonic thrusts, related to the intense orogenic activity of the region, and widespread ancient landsliding, as such, leaving the clayey layers severely sheared, and the rocky strata generally fractured and floating as disarranged rock masses in the soil matrix.

Description of the Selected Sites

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Bovino

Findings

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