Application of crosshole electrical resistivity tomography measurements under the influence of horizontally slotted plastic cased boreholes
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Bibliographic record
Abstract
ABSTRACT In this work, we study the performance of cross‐hole electrical resistivity tomography measurements by employing different electrode array configurations in plastic polyvinyl chloride (PVC) cased and horizontally slotted observation boreholes by inserting a multi‐electrode cable directly into the borehole. Preliminary cross‐hole electrical resistivity tomography measurements in PVC cased boreholes related to an underground tunnel construction showed poor data quality. This was attributed to the borehole‐fluid effect caused by the PVC casings. An experimental study was conducted to support this hypothesis by setting up various simulations in a water tank, using different PVC casings with various slot densities, and different electrode array configurations. We conclude that the applicability of various measurement setups depends mainly on the acquisition protocol and, to a lesser extent, on the slot density of the PVC casing. Among the different array configurations considered, the pole–dipole array with the potential measuring electrodes being placed in a separate borehole to the current electrodes provide the most robust and reliable results, even for low slot density PVC casings. Besides, denser borehole slot configurations result in better data quality, though to a different extent for the examined protocols. A minimum slot density criterion of at least six slots/electrode spacing is proposed, regardless of the electrode array. The experimental findings are finally evaluated against real field measurements associated with the construction of an underground tunnel of the new Thessaloniki Metro, verifying the pole–dipole array's superior behaviour for this type of measurement configuration. Finally, for those cases where the aspect ratio (hole depth/hole separation) is limited, we propose a modified borehole‐to‐surface configuration with the current electrodes placed outside the boreholes. The overall results indicate that slotted PVC cased observation boreholes (e.g., conventional piezometers), typically constructed as part of many infrastructure monitoring projects, can be efficiently employed for electrical resistivity tomography mapping, generating a new perspective for geoelectrical prospecting. This measuring approach exhibits a significant advantage. The use of pre‐existing boreholes reduces the overall survey costs, reliability, and effort, while also providing high‐resolution subsurface images, especially in urban environments.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
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Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it