Three-dimensional centrifuge and numerical modeling of the interaction between perpendicularly crossing tunnels
Why this work is in the frame
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Bibliographic record
Abstract
Tunnel driving inevitably induces changes in stress and deformation in the ground, which could cause ultimate and serviceability problems to an adjacent tunnel. The effects of induced stress on an existing tunnel and crossing-tunnel interaction are still not fully understood. In this study, a series of three-dimensional centrifuge tests were carried out to investigate the responses of an existing tunnel in sand to the excavation of a new tunnel perpendicularly below it. Three-dimensional tunnel advancement was simulated using a novel technique that considers the effects of both volume and weight losses. This novel technique involves using a “donut” to control volume loss and mimic soil removal in-flight. To improve fundamental understanding of the stress transfer mechanism during the new tunnel advancement, measured results were back-analyzed three-dimensionally using the finite element method. The maximum measured settlement of the existing tunnel induced by the new tunnel constructed underneath was about 0.3% of tunnel diameter, which may be large enough to cause serviceability problems. The observed large settlement of the existing tunnel was caused not only by a sharp reduction in vertical stress at the invert, but also by substantial stress transfer of overburden pressure at the crown. The section of the existing tunnel directly above the new tunnel was compressed vertically because the incremental normal stress on the existing tunnel was larger in the vertical direction than in the horizontal direction. The tensile strain and shear stress induced in the existing tunnel exceeded the cracking tensile strain and allowable shear stress limit given by the American Concrete Institute.
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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 | 0.001 |
| 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 it