Full-Scale Testing of Large Diameter Steel Pipes under Soil Compaction and External Load
Bibliographic record
Abstract
Pipes are buried as the safest method of transporting natural resources, such as oil and gas. 86% of the existing pipes buried in Alberta, Canada are made from steel. Large diameter pipes are designed and buried to replace the old ones and improve the oil transportation capacity. For buried pipes, heavy truck load is considered as one of the most important factors influencing the pipe behavior. Soil compaction during the pipe installation has been proven to affect the pipe behavior. The main objective of this study is to investigate the buried pipe behavior under soil compaction and truck load. The study is performed in three parts, i.e., laboratory soil tests, full-scale prototype tests on two Grade X52 steel pipes, and development and validation of a new semi-empirical method to predict pipe deformation.Firstly, the laboratory soil test results indicate that the soil modulus decreases with increasing water content, while it tends to increase slightly with confining pressure. The undrained shear strength of compacted silty sand increases with decreasing water content and increasing confining pressure. Secondly, the prototype test results illustrate that, during the soil compaction, the so-called peaking effect is detected on both pipes mainly due to the compaction pressure at the pipe sides. After that, the pipe is vertically compressed under overburden. The measured pipe strains increase with increasing applied load and decreasing cover depth. Perforation in pipe would induce stress concentration near the opening, thereby increasing the pipe strain. Increasing water content decreases the soil stiffness. As a result, a higher percentage of the applied load is taken by the pipe, and the pipe deformation is magnified. Compared to a static loading condition, pipe behavior under dynamic load is more complicated, and affected by factors including road roughness, cover depth, truck load, and truck moving speed.Thirdly, based on the results from the prototype tests, a semi-empirical method is proposed to predict the pipe stress and deflection in two steps. Pipe deformation is mainly attributed to the peaking effect and the overburden.
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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) | 0.001 | 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 | 0.001 | 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".