Jointly reconstructing ground motion and resistivity for ERT-based slope stability monitoring

Abstract

Electrical resistivity tomography (ERT) is increasingly being used to investigate unstable slopes and monitor the hydrogeological processes within. But movement of electrodes or incorrect placement of electrodes with respect to an assumed model can introduce significant resistivity artefacts into the reconstruction. In this work, we demonstrate a joint resistivity and electrode movement reconstruction algorithm within an iterative Gauss-Newton framework. We apply this to ERT monitoring data from an active slow-moving landslide in the UK. Results show fewer resistivity artefacts and suggest that electrode movement and resistivity can be reconstructed at the same time under certain conditions. A new 2.5-D formulation for the electrode position Jacobian is developed and is shown to give accurate numerical solutions when compared to the adjoint method on 3-D models. On large finite element meshes, the calculation time of the newly developed approach was also proven to be orders of magnitude faster than the 3-D adjoint method and addressed modelling errors in the 2-D perturbation and adjoint electrode position Jacobian.

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

“…In particular, this method is applied for recognitions of lithostratigraphic sequences and the geometry of the landslide's body, identifying the sliding surfaces between the slide material and the underlying bedrock and the location high-water content areas (Panek et al 2008;Dardé et al 2013;Holec et al 2013;Dostál et al 2014;Tomecka-Suchoń et al 2017;Crawford and Bryson 2018). It is also used for the building and monitoring of high-resolution geological models (both 2D and 3D) and presenting results in a 4D system (Lebourg et al 2005;Jomard et al 2010;Chambers et al 2011;Merritt et al 2014;Uhlemann et al 2017;Boyle et al 2018;Břežný et al 2018). Information obtained from ERT method is useful for engineering geologists and geomechanics to define the geological setting of the investigated subsoil, reconstruct the geometry of landslide body and volume of the slide material and locate the possible sliding surface and lateral boundaries of the landslide-which are necessary to plan mitigating activities and interventions (installation of a drainage system, stabilization of landslide, etc.)…”

Geophysical Monitoring of Moisture‐Induced Landslides: A Review

“…These positional measurements need to be taken at a frequency at which movement can be captured. Recent advances in geophysical inversion have been able to recover electrode movements over time, and therefore incorporate the movements in to the processing of ER data to prevent the introduction of data artifacts by electrode movements (Boyle et al, ; Loke et al, ; Wilkinson et al, ; Wilkinson et al, ). This has been an important step in developing the autonomy of semipermanent installations, and has greatly improved the data quality available from such campaigns (Uhlemann et al, ).…”

Applying Electrical Resistivity Tomography in Ornamental Stone Mining: Challenges and Solutions

“…The topography of the survey area and the exact electrode location is usually included in the data inversion, as they are known to have a significant impact on the measured data [43][44][45][46][47][48]. It has also been shown that topographic features outside the actual survey area can impact upon the measured resistivity data and can lead to misinterpretation, especially in the case of 2D data analysis [49,50].…”