Effect of Erosion Voids on Rigid Sewers of Non-Circular Shape
Bibliographic record
Abstract
Water ingress into leaking sewers and culverts may lead to development of erosion voids adjacent to the structure. The loss of lateral soil support then results in changes to the distribution of earth pressures on the structure, and significant enhancement of peak bending moments, and hoop thrusts. This study extends previous work on buried circular rigid (concrete or clay) pipes to examine the earth load response of buried pipes with noncircular cross sections in the presence of erosion voids. Both horizontally oriented and vertically oriented ellipses were analyzed using the ABAQUS software package. A range of void sizes was considered, where size is quantified using void angle—the angle over which there is loss of soil support on the exterior of the pipe. Five values were examined—where the soil is intact (0 degrees), and where void angles are 30, 60, 90, and then 120 degrees. Earth pressures increase significantly where the soil contacts the pipe above and below the zone of zero contact, with those local increases growing substantially as the extent of the erosion void increases. Peak thrusts at the pipe springlines also increase, as the pipe is required to carry more of the weight of the overlying soil load (less is transferred around the pipe through the soil). Increases in peak bending moments at the crown, invert and springlines are very significant, and could be expected to render the flexural resistance of a reinforced concrete pipe well below the increased moment demands. The springline of the pipe adjacent to the void had the largest increases in both thrust and moment, and for some pipe shapes could become the location of controlling flexural failure (instead of the normal location at crown or invert).
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".