A study of stability analysis of pyroclastic covers based on electrical resistivity measurements

TL;DR

This study introduces a semi-empirical geophysical method to assess slope stability in pyroclastic soils, providing a more comprehensive understanding than traditional point-based measurements, demonstrated through seasonal surveys on the Sarno Mountains.

Contribution

The paper presents a novel application of resistivity-based geophysical Factor of Safety for slope stability analysis in pyroclastic terrains, integrating geophysical and geotechnical data.

Findings

Resistivity tomography maps reveal seasonal variations in slope stability.

Comparison shows advantages and limitations of the geophysical approach.

Application on Sarno Mountains demonstrates practical utility in landslide-prone areas.

Abstract

Usually, the degree of stability of a slope is quantified by the Factor of Safety whose values depend on physical and mechanical soil properties analyzed on samples of much reduced sizes or referring to very small soil volumes around porous probes. To overcome the limit of punctual information, we propose a semi-empirical approach based on the use of geophysical methods and the employment of a geophysical Factor of Safety recently introduced by the authors in terms of local resistivities and slope angles. In this paper, we show an application of our proposal on a test area of about 2000 m2 on Sarno Mountains (Campania Region - Southern Italy), where shallow landslides involving pyroclastic soils periodically occur triggered by critical rainfall events. Starting from two resistivity tomography surveys performed on the test area in autumn and spring, we obtained maps of the geophysical Factor of Safety at different depths for the two seasons. We also estimated the values of the Factor of Safety by using the infinite slope model in the dry and saturated scenario. A comparison between the values of the geophysical and geotechnical Factor of Safety shows advantages and disadvantages of our approach.