Instability of dykes at Seven Sisters Generating Station
Bibliographic record
Abstract
Water-retention dykes at Seven Sisters Generating Station in Manitoba have experienced irregular instabilities since they were heightened in the late 1940s. An investigation was undertaken to compare three locations at the site, one section of dyke that had experienced previous instability, a second section that had remained stable, and a third, background location that had not experienced dyke loading. The investigation included laboratory tests, field tests, and computer modelling. The laboratory tests indicated anisotropic stiffness and brittle strain-softening behaviour in the highly plastic clay beneath the dykes. Results from the stable and unstable sections showed greater brittleness and anisotropy at the unstable section. Pore fluid chemistry tests for cation and anion concentrations showed considerable reductions in concentrations of calcium and sulphate beneath the dykes compared with those of the background section. This suggested leaching of gypsum in the foundation soil. Computer modelling was done using seepage, stressdeformation, and slope stability software. Results indicated that the stable and unstable sections both had safety factors greater than unity if "post-peak" strengths were used. Both were close to unity if residual strengths were used. The results suggest that time- and location-dependent depletion of gypsum cementation bonds caused by seepage beneath the dykes has increased the brittleness and anisotropy and reduced stability with time.Key words: clay, cementation, gypsum, leaching, anisotropy, brittleness.
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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 | 0.000 |
| 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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".