Physical and numerical investigation of deformation mechanisms of jointed pipelines due to passive face instability of EPB shield tunnelling
Bibliographic record
Abstract
The serviceability and safety of existing pipelines may be adversely affected by differential ground movements resulting from inappropriate control of face pressure of EPB (earth pressure balance) shield tunnelling. However, previous studies mainly concentrated on deformation mechanisms of continuous pipelines resulting from tunnel face active instability. In this study, 16 three-dimensional physical model tests were conducted to explore the effects of tunnel cover-to-diameter ratio ( C/D) and relative tunnel-pipeline position ( H/D) on deformation mechanisms of jointed pipeline due to tunnel face passive instability. Moreover, a systematic numerical parametric study was performed to develop calculation charts for estimating joint rotation angle subjected to ground heaves. For tunnel C/D ratios of 1.0 and 1.5, the existing jointed pipeline at 0.7 D and 1.2 D ahead of tunnel face experiences the highest heave and joint rotation angle, respectively. By increasing C/D ratios from 1.0 to 1.5, the maximum pipeline deformation decreases by up to 84.5%. A dimensionless group, namely relative pipe segment-soil stiffness, is proposed to distinguish relatively rigid and flexible jointed pipelines, and normalised pipe segment length and relative pipe–soil stiffness are also proposed to establish calculation charts for predicting joint rotation angles of relatively rigid and flexible jointed pipelines, respectively.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".