Instrumented Becker Penetration Test for Improved Characterization of Gravelly Deposits
Bibliographic record
Abstract
The Becker penetration test (BPT) is a widely used tool for characterization of gravelly soils, especially for liquefaction potential assessment. BPT results are affected by the variability of the energy transferred from the hammer to the drill string and the distribution of the forces and deformations along the shaft and at the tip. Interpretation of BPT data is particularly challenging in dam foundations where the shaft resistance of the thick dense shell can be significant compared with the tip resistance of underlying loose foundation layers. Current interpretation methods that utilize above-ground PDA-type or bounce chamber pressure measurements have had limited success in accurately separating the shaft and tip resistance and thus detecting potentially weak problematic layers at depth. A Becker drill string was instrumented to allow measurement of the dynamic force and acceleration at the tip in addition to the conventional above-ground location. This provided direct measurements of the energy transferred to the drill string by the hammer and the actual energy that is delivered to the soil below the driving shoe. Blow counts are corrected using the energy measured at the tip and a correlation between this normalized blow count Nb30 and SPT N60 is explored.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".