Long Distance Curved Microtunnelling Raises the Bar in Ontario
Bibliographic record
Abstract
Prior to 2012, the integration of designed vertical or horizontal curves into microtunnel alignments was unheard of in Ontario.Straight and relatively short microtunnels, less than 200m long, were the local accepted industry standard.Following the release of a large number of infrastructure projects in the suburban Greater Toronto Area (GTA), clients and design consultants encouraged contractors to present value engineered alternatives to proposed project alignments and construction methods.Such an initiative has allowed contractors to develop cost effective solutions, which harnessed the application of state-of-the-art microtunnelling methods and equipment.As a result, several recent projects now feature pre-designed curved microtunnels as part of the tender documents.This paper discusses, in technical detail, three recent projects, whereby, long distance curved microtunnels were successfully constructed.Each of the projects had tunnel drives exceeding 300m in length, ranging in diameter from 1200mm ID to 1500mm ID, incorporating the use of Vertical, Horizontal, and Spatial Curves.Critical parameters such as pre-project planning and engineering are highlighted, while the importance of post-tunnelling assessments is also discussed.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.005 | 0.003 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".