ERT-based experimental integrated approach for soil hydrological characterization in rainfall-induced shallow landslides prone areas

Abstract

Shallow landslides triggered by heavy rainfalls are slope instabilities, developed in the most superficial eluvial layers, involving the first 2 m from the ground level. A crucial predisposing factor in shallow landslides occurrence is the soil water content, generally measured trough sensors installed in the first soil layers. However, despite being a very precise approach, this monitoring technique provides for a site-specific dataset. An integrated method to extend the hydrological characterization from site-specific to slope scale is presented, combining geotechnical analyses, field data monitoring, and geophysical investigations, in two experimental test sites located on Italian Apennines. Ten Electrical Resistivity Tomographies (ERT) of the first soil horizons were performed through different array geometries (2D-3D-Time-Lapse), calibrated and interpreted basing on stratigraphic logs, trenches, and monitored soil water content field data. The test sites colluvial covers composition was analyzed and compared to resistivity values to build conceptual hydrogeological models of the deep-water circulation. In addition, two time-lapse (4D) ERT surveys were performed in both test sites simulating very intense precipitations, to determine the resistivity variations at different soil drainage conditions, thus estimating the average bulk permeability. Bulk permeability can be also a useful input parameter for slope stability models, widely employed in engineering practices. This integrated method proved to be very useful for the hydrogeological characterization of the subsoil at slope scale, where it is susceptible to slope instability, improving the knowledge of water circulation, as well as the bulk permeability heterogeneities, which are shallow landslides triggering parameters.

Evaluating the Effectiveness of Wenner Modes Configurations for Resistivity-Based Moisture Monitoring in Compressed Earth Bricks

“…Electrical resistivity techniques have emerged as a powerful non-destructive testing and characterization tool in various fields, particularly in geotechnical engineering (Aizebeokhai et al, 2018;Ducut et al, 2022;Muchingami et al, 2012;Vivaldi et al, 2024). These methods have been extensively researched, developed, and applied over the past several decades, gaining recognition for their versatility, reliability, and non-destructive nature.…”

“…By measuring the electrical resistance of a material or medium, electrical resistivity techniques provide valuable insights into its internal structure, composition, and properties. In geotechnical engineering, these methods have proven highly useful for measuring soil resistivity, characterizing subsurface conditions (Chambers et al, 2007;Evangelista et al, 2017;Fäth et al, 2022;Ungureanu et al, 2017;Vivaldi et al, 2024), assessing soil properties (Asare et al, 2022;Besson et al, 2004;Hebbache & Boubaya, 2022;Vivaldi et al, 2024), delineating kaolinized and aquifer formations (Siva Prasad & Venkateswara Rao, 2022), characterizing underground cavities (Mihraje et al, 2022), and monitoring groundwater (Ma et al, 2023;Muchingami et al, 2012)... The electrical resistivity techniques allow for rapid and cost-effective data acquisition over large areas, making them suitable for preliminary site investigations and feasibility studies.…”