Three-dimensional analysis of unanticipated behavior of a deep excavation
Bibliographic record
Abstract
A three-dimensional (3D) effective stress finite element analysis, modified to account for hydrofracturing and gassy soil behavior, is used to examine the potential for the venting of water and gas from a bedrock aquifer and through 13–14 m of low permeability clayey silt between the base of the excavation and the bedrock following excavation to about 24 m in an approximately 40 m thick clayey silt deposit. The clayey deposit contained sand lenses with dissolved gas. The analysis predicts that the exsolution of this dissolved gas, caused by a reduction in total stress due to the excavation, results in liquefaction of the sand in the lenses and consequent lateral deformations of the side slopes. The analysis predicts hydrofracturing through the remaining clayey silt when the excavation reaches its final depth and this explains the venting of water and gas from the underlying aquifer that was observed above a local bedrock high. The presence of gassy sand lenses created weak zones within the clayey deposit that influenced the path of the hydrofracturing. However, the analyses suggest that, for the depth of excavation and bedrock elevation examined, hydrofracturing and subsequent venting would have occurred even if there had been no sand lenses.
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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 | 0.001 |
| 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 | 0.001 | 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".