OhmPi: An open source data logger for dedicated applications of electrical resistivity imaging at the small and laboratory scale

Clément, Rémi; Fargier, Yannick; Dubois, Vivien; Gance, Julien; Gros, Emile; Forquet, Nicolas

doi:10.1016/j.ohx.2020.e00122

Cited by 15 publications

(7 citation statements)

References 42 publications

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“…This could have allowed using more electrodes to obtain a better reconstruction of the resistivity distribution, along with faster measurement sequences. Another solution would be the use of flexible, low‐cost devices, specially dedicated to laboratory experiments such as the OhmPi resistivity metre (Clément et al ., 2020). Finally, other optimization methods (e.g., optimizing the resolution matrix; Wilkinson et al ., 2006) could be tested and compared to the results originating from the optimization of the sensitivity matrix.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

Geophysical monitoring of a laboratory‐scale internal erosion experiment

Maalouf

Bièvre

Khoury

2022

Near Surface Geophysics

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Earth dams are structures used worldwide for water management. Their failure over time is notably due to water seepage generating internal erosion. There is a growing need to detect the processes at work as early as possible. This study presents a controlled laboratory experiment aimed at detecting and monitoring water seepage into a soil sample. The experiment was monitored with electrical resistivity tomography, velocimeters and video recording. The video recording of the downstream side of the soil sample shows successive episodes of mass movements associated with a progressive water flow increase. The electrical resistivity tomography, limited by a low temporal resolution, shows an evolution of the resistivity in agreement with the evolution of the soil sample (e.g., saturation and mass movements), but with strong limitations regarding the robustness of the results. The continuous seismic recording reveals extra rupture episodes that occur inside the volume of the soil sample, which were not recorded by the video. Their distribution in time and energy illustrates strongly nonlinear changes in the soil sample, with several phases of acceleration. A controlled source monitoring using external repetitive events allows probing the medium with an enhanced temporal resolution compared to electrical resistivity tomography. The apparent seismic velocity of the soil sample reveals a nonlinear decrease, high at the beginning of the experiment, and then stalled until the different mass movements enlarge the amount of water inside the sample along with the water flow. The different techniques used, especially seismic monitoring, describe a complex and strongly nonlinear process of internal erosion centred around the coupling between water flow and internal damage. Finally, these findings suggest that seismic methods could be able to distinguish the four different phases of internal erosion (namely, initiation, continuation, progression and failure) discussed in the geotechnical literature.

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Section: Interpretation and Discussionmentioning

confidence: 99%

Geophysical monitoring of a laboratory‐scale internal erosion experiment

Maalouf

Bièvre

Khoury

2022

Near Surface Geophysics

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“… 2012 ), such as the OhmPi instrument (Clement et al. 2020 ). Optimized data acquisition protocols for ERT surveys have been studied since the beginning of the 2000s with the work of Stummer et al.…”

Section: Emergence Challenges and Perspectives Of Tl-ert For Mining W...mentioning

confidence: 99%

A Review on Applications of Time-Lapse Electrical Resistivity Tomography Over the Last 30 Years : Perspectives for Mining Waste Monitoring

et al. 2022

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Mining operations generate large amounts of wastes which are usually stored into large-scale storage facilities which pose major environmental concerns and must be properly monitored to manage the risk of catastrophic failures and also to control the generation of contaminated mine drainage. In this context, non-invasive monitoring techniques such as time-lapse electrical resistivity tomography (TL-ERT) are promising since they provide large-scale subsurface information that complements surface observations (walkover, aerial photogrammetry or remote sensing) and traditional monitoring tools, which often sample a tiny proportion of the mining waste storage facilities. The purposes of this review are as follows: (i) to understand the current state of research on TL-ERT for various applications; (ii) to create a reference library for future research on TL-ERT and geoelectrical monitoring mining waste; and (iii) to identify promising areas of development and future research needs on this issue according to our experience. This review describes the theoretical basis of geoelectrical monitoring and provides an overview of TL-ERT applications and developments over the last 30 years from a database of over 650 case studies, not limited to mining operations (e.g., landslide, permafrost). In particular, the review focuses on the applications of ERT for mining waste characterization and monitoring and a database of 150 case studies is used to identify promising applications for long-term autonomous geoelectrical monitoring of the geotechnical and geochemical stability of mining wastes. Potential challenges that could emerge from a broader adoption of TL-ERT monitoring for mining wastes are discussed. The review also considers recent advances in instrumentation, data acquisition, processing and interpretation for long-term monitoring and draws future research perspectives and promising avenues which could help improve the design and accuracy of future geoelectric monitoring programs in mining wastes.

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“…Research over the last few decades has led to the development of resistivity meters known commercially as georesistivimeters. This equipment is fundamental for geoelectric exploration campaigns; however, companies that manufacture such instruments are very concerned with the quality of their measurements as well as their robustness for fieldwork (Clement et al, 2020;Pasquali et al, 2017;Toll, 1999), making this instrument sophisticated and expensive.…”

Section: Introductionmentioning

confidence: 99%

“…In this regard, it is worth mentioning the work of Hassan (2014) and Clement et al (2020), who developed automated georesistivimeters for low-cost investigations to disseminate the method from a robust and flexible tool for small-scale experiments, using basic benchtop electronic equipment for testing and feasibility in the conceptual development of the instrument. In this work, the preliminary results obtained with the application of electroresistivity are reported, with the construction of a prototype of a modular professional resistivimeter, automated and programmable, aim-A.…”

Section: Introductionmentioning

confidence: 99%

Design and construction of an automated and programmable resistivity meter for shallow subsurface investigation

Júnior

Ponte-Neto²,

Wiermann³

2023

Geosci. Instrum. Method. Data Syst.

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Abstract. Geoelectrical resistivity is an excellent method to investigate the structural composition of shallow subsurfaces. However, existing commercial equipment is typically expensive and often requires proprietary accessories and software to provide full system functionality. The objective of this study was to develop a multichannel, modular, automated, and programmable geo-resistivity meter capable of user customization and programming. To this end, a conceptual prototype was built based on free software and open hardware technologies as a low-cost alternative to commercial equipment while maintaining the accuracy and quality of the data at the same level. The prototype was based on electrode multiplexing to make the switching process more efficient by reducing cabling complexity, whereas synchronous demodulation for signal detection was employed, providing strong rejection of spurious electrical noise, typical of urban areas where such equipment is frequently used. The results demonstrate the feasibility of this project and an important academic contribution to open-source instrumental research.

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OhmPi: An open source data logger for dedicated applications of electrical resistivity imaging at the small and laboratory scale

Cited by 15 publications

References 42 publications

Geophysical monitoring of a laboratory‐scale internal erosion experiment

Geophysical monitoring of a laboratory‐scale internal erosion experiment

A Review on Applications of Time-Lapse Electrical Resistivity Tomography Over the Last 30 Years : Perspectives for Mining Waste Monitoring

Design and construction of an automated and programmable resistivity meter for shallow subsurface investigation

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