An acoustic emission slope displacement rate sensor — case studies
Bibliographic record
Abstract
Research over a period of 20 years has resulted in development of a battery operated unitary acoustic emission (AE) sensor which, when used with a standard active waveguide installation, can quantify soil slope displacement rates continuously and in near real-time. The active waveguide is installed in a borehole through existing or anticipated shear zones, and comprises a steel tube with granular soil surround. The AE sensor is located at ground level and with the waveguide is encased in a cover. Deformation of the slope strains the granular backfill, which generates AE through rearrangement of the particles. The AE propagate as stress waves along the steel tube to the ground surface where they are detected and quantified by the sensor, which is used to provide alert text messages if pre-determined thresholds are exceeded. The use of a reproducible waveguide allows standard interpretation of the generated AE to provide information on soil slope displacement rates, and the granular soil backfill generates measureable AE when the system is installed in slopes formed in ‘quiet’ fine grained soils. The approach monitors AE at high frequencies to exclude environmental background noise and hence ensure that false alarms are not generated. In rock slopes, the grouted waveguide is passive, with measured AE generated by rock deformation mechanisms. The sensors have been deployed on multiple sites in the UK and in Italy, Austria and Canada. At all sites performance of the AE sensors has been compared with traditional deformation monitoring instrumentation including ShapeAccelArray, inclinometer, extensometer and time-domain reflectometry. Measurements from these field studies have demonstrated that generated AE are proportional to slope displacement rates. This paper outlines the AE measurement and the interpretation techniques developed, and presents field comparisons of measured AE trends and slope displacement rates obtained from extended trials at several sites. It is concluded that the AE technique can be used as a reliable early warning system for soil slope instability. Applications in rock slopes are promising but further work is required to link detected AE to rock deformation mechanisms and hence to derive thresholds as a basis for early warnings.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".