Large Riprap Design and Construction—Big Bar Landslide
Bibliographic record
Abstract
The Big Bar landslide occurred on a remote section of the Fraser River, 64 km north of Lillooet, British Columbia, and created a barrier to the vital seasonal northward Fraser River salmon migration. Intensive efforts were made by Canada Department of Fish and Oceans in 2019 as an emergency response to stabilize the slide source and to remove large boulders and rockfall debris from the river. Early in 2021, Kiewit design teams had nearly finalized plans for construction of a roughened embankment for volitional passage and a concrete fish ladder. However, ongoing rockfall hazards prevented any work commencing on the fish ladder structure. The roughened slope design was largely completed as this embankment was planned to support the concrete fish ladder. In lieu of the fish ladder, the slope of the roughened embankment was extended. Construction of the roughened embankment consisted of large riprap with a characteristic size of 1.5 m with rock material produced from on-site sources. Modeling of the hydraulic performance was accomplished with depth-averaged two-dimensional analysis (USBR SRH-2D). Spatial distributions of shear stress and velocity were computed over the embankment for determination of riprap stability as well as provide an environment for volitional fish passage. A thorough inspection and testing protocol (ITP) for rock material and placement were followed. ITP implementation included use of image segmentation gradation analysis and other testing methods. Heroic construction efforts through the winter of 2020–2021 in the tough environment of the Fraser River completed the roughened embankment in time for the spring freshet. Flow in the Fraser River in June of 2021 peaked at approximately 6,100 m3/s with the roughened embankment remaining completely stable.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
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".