Sinkhole Locating and Corrosion Quantification with Pipe Penetrating Radar
Bibliographic record
Abstract
Pipe penetrating radar (PPR) is the underground in-pipe application of ground penetrating radar (GPR), a non-destructive testing method that can detect defects and cavities within non-ferrous (reinforced concrete, vitrified clay, PVC, HDPE, etc.) pipes. The key advantage of PPR is the unique ability to map pipe wall thickness and deterioration including voids outside the pipe, enabling accurate predictability of needed rehabilitation or the timing of replacement. This paper presents recent advancement of PPR inspection technology together with selected case studies. The century old Broadway sewer main in Everett, WA, is a combination of a 30” reinforced concrete (RC) pipe and a 36” brick pipe. Little information is known about the condition of these pipes and the owners needed structural information beyond the usual closed circuit television (CCTV) in order to plan long term management of these critical assets. Over 16,000 ft of high resolution PPR line data were collected via robotic inspection. Due to the highly complex nature of the geophysical data, data processing and interpretation was a critical component of this project. The PPR results revealed that there are variations in the rebar cover in segments of the RC pipe. Although the average minimum rebar cover (depth of the first layer of rebar measured from the inner surface of the pipe wall) in almost every pipe segment appears to be sufficient (more than 0.75"), local anomalies occur along the pipe. No voids were detected outside the concrete pipe. In the second case study PPR was used for the condition assessment of asbestos cement (AC) pipes. AC pipes form a significant component of the water distribution and sewer collection systems in many cities. A majority of these pipes appear to be approaching the end of their useful life. The ability to accurately and cost-effectively assess the wall thickness of asbestos cement pipe has become a critically important issue for pipe owners. A new, high resolution PPR system, the SewerVUE AC Pipe Scanner (ACPS) was developed and successfully deployed in a live 10” AC pipe in Surrey, BC, Canada. Using new, high frequency antennae, the PPR inspection accurately mapped the remaining wall thickness.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| 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".