Investigating rock anchorage failure at major road cut in Wales
Bibliographic record
Abstract
Rock anchorage failures occurring only 6 years after installation to support a major cutting on the A5 trunk road west of Corwen in North Wales were exhaustively investigated, ultimately resulting in their removal and partial replacement. The failures in Glyn Bends rock cutting were detected when head assembly components were found on the ground during a routine inspection. The investigation of the 120-year design life double-corrosion-protected anchorages included the innovative use of endoscopy, selectively supported by subsequent physical dismantling and metallurgical examination. On the basis of the investigation and the subsequent recovery of some of the installed anchorages, it was confirmed that at least 24% of the anchorages originally installed had their factory corrosion protection fatally compromised by partial removal. This was aggravated by the omission of the caps, which allowed the protective grease to escape, and placing many anchorages in recesses which aggravated surface corrosion. Metallurgical investigation emphasised that corrosion protection is critical to very-high-yield steels. No records of the alterations made were ever produced. The trunk road had to be closed at short notice for 8 months on public safety grounds while the main cutting face was reprofiled to a safe unsupported angle on the north side and re-anchored on the south side.
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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 | 0.001 | 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 | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".