Instrumentation of the shotcrete lining in the Canadian National Railways Tunnel, Vancouver, B.C.
Bibliographic record
Abstract
The Canadian National Railways Tunnel in Vancouver, B. C. is the first tunnel in North America to be driven with a temporary and permanent support system of coarse-aggregate shotcrete in lieu of steel arch sets and formed concrete. In order to determine the function of the shotcrete lining and to aid in the decision to use the lining as a permanent lining, an instrumentation program was undertaken. Surface photoelastic strain gauges and imbedded hydraulic pressure cells were used to determine in situ stresses and strains. The measurements show that the lining has achieved a relative equilibrium level at three representative measurement points, and that nowhere have the measured stresses and strains been excessive, nor have they even approached allowable design values. The function of the shotcrete lining as a support system has been shown to differ from that attained by steel arch supports. The use of shotcrete for support of the Canadian National Railways tunnel resulted in considerable economic savings.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".