Instrumented Becker Penetration Test. I: Equipment, Operation, and Performance
Bibliographic record
Abstract
The Becker penetration test (BPT) is a widely used tool for characterizing gravelly soils, especially for liquefaction assessment. Interpretation of BPT data is complicated by the variable energy transferred from the hammer to the drill and by the shaft resistance that develops along the drill string which generally increases with penetration depth. Existing BPT interpretation methods that use above-ground measurements have had limited success in accurately separating the shaft and tip resistance. Therefore, penetration resistance with depth cannot be reliably predicted. An instrumented Becker penetration test (iBPT) that measures acceleration and force directly behind the driving shoe in order to compute the energy delivered to the driving tip was developed and integrated into the standard closed-ended Becker drill system. The equipment and data acquisition system are described in this paper. The analysis procedure used to compute energy-normalized blow count values and produce continuous penetration resistance profiles is outlined. The energy-normalized blow count profiles generated are shown to be independent of penetration depth, predrilling depth, shaft resistance magnitude, and hammer operating conditions. In particular, the efficacy of a residual energy-based normalization scheme is demonstrated. Finally, a discussion regarding energy measurements, locked-in stress at the drill string tip, and the use of the pull-back and redrive procedure is presented.
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How this classification was reachedexpand
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 | 0.000 |
| 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)
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 teacher head, 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".