Geophysical and geotechnical approach to a landslide stability assessment: a case study

Abstract

Landslides are complex phenomena, and the main factors that have a significant impact on their behavior are changes in slope inclination geometry and changes in water conditions. The main purpose of this work was to evaluate current conditions of the landslide in Brzozówka, near Cracow (Poland), and analyzing how different saturations of soil influence the stability of the landslide. The combination of geophysical and geotechnical research, such as electrical resistivity tomography (ERT), cone penetration testing, drilling and laboratory tests as well as a comprehensive analysis of their results, provided reliable information on the geological structure and geotechnical parameters of the landslide. The results were used in numerical simulations of the landslide stability, in which a two-phase model (soil and water) was assumed that included the effective soil strength parameters and the transient flow conditions as well as a partial saturation zone. The sliding surface obtained from the numerical modeling was almost flat, which was confirmed by the ERT method. It was proved that the landslide occurred when the saturation of the upper part of the slope exceeded 0.8. Obtained results are useful for engineering practice.

Characterization of Sobradinho landslide in fluvial valley using MASW and ERT methods

“…However, this was not observed in the current study because the measurements were taken in the dry season, where the soil was mostly dry at shallow depths. A similar phenomenon has been reported by Pasierb et al (2019). Thirdly, a continuous low resistivity material was also found, which might be related to a possible permeable path through the water, whose water from the Contagem river percolates into the landslide mass where it can also build pore water pressure, which can be a possible trigger for its reactivation.…”

“…The electrode spacing of 5 and 8 m were adopted because DD array sometimes misleads the landslide slip surface estimation, if large electrode spacing (current and potential) is applied (Loke 2004;Rezaei et al 2019). Based on the study objectives, Wenner-Schlumberger and DD arrays are the most common arrays adopted for the landslide studies due to good depth range and the best horizontal resolution (Reynolds, 2011;Pasierb et al 2019). Because the target landslide in the present study is shallow, DD array was adopted for the calculation of the shallow slip surface and permeable path delineation at high spatial resolution.…”

Analysis of Geotechnical-Assisted 2-D Electrical Resistivity Tomography Monitoring of Slope Instability in Residual Soil of Weathered Granitic Basement

“…Slope movement events that resulted in landslide have wrecked severe havoc and damage to lives and infrastructures with an estimated loss of several billions of dollars across the world (Chandarana, 2016;Sidle and Bogaard, 2016;Winter et al, 2016;Soto et al, 2017;Wang et al, 2017;Bordoni et al, 2018;Di Traglia et al, 2018;Tomás et al, 2018;Moragues et al, 2019;Yang et al, 2019;Kirschbaum et al, 2020). The impact of damages caused to lives and infrastructure as well as mitigation and management of this natural hazard has been the subject of research for decades (Abidin et al, 2017;Bordoni et al, 2018;Pasierb et al, 2019). However, research work on the area of slope instability monitoring to predict future occurrence of landslide to prevent loss of lives and properties has not yet been fully demonstrated (Chae et al, 2017;Intrieri et al, 2019;Park et al, 2019).…”

“…To adequately obtain information about the soil-water conditions in the subsurface structure, a noninvasive geophysical technique of ERT has been adopted by several researchers (Brillante et al, 2015;Giocoli et al, 2015;Hübner et al, 2015;Abidin et al, 2017;Angelis et al, 2018;Boyle et al, 2018;Cavalcanti et al, 2018;Gaffney et al, 2018;Gunn et al, 2018;Olabode and Ocho, 2018;Tomás et al, 2018;Pasierb et al, 2019). It provides a very fast, cheap, and efficient survey technique to characterize landslide-prone slopes (Pasierb et al, 2019). Electrical resistivity is sensitive to changes in the pore fluid resistivity and fluid saturation as the mode of current flow in the subsurface is through electrolytic conduction in the pore fluid (Hen-Jones et al, 2017).…”

“…Recent studies on landslides have shown that ERT is suitable to monitor soil water content variations induced by rainfalls among other methods such as seismic refraction, seismic reflection, and self-potential and ground penetrating radar (Baroň and Supper, 2013;Boyle et al, 2018;Hojat et al, 2019;Whiteley et al, 2019). ERT is applied in order to characterize lithostratigraphic sequences and geometry of the sliding body, identifying the sliding surfaces between the slide materials and underlying bedrock and location of high-water content areas or zones (Tomecka-Suchoń et al, 2017;Pasierb et al, 2019).…”