Rotation of principal axes and changes of stress due to mine-induced stresses
Bibliographic record
Abstract
This research project comprises stress monitoring, primarily of the changes induced by longwall mining or destress blasting, which was realized in a mine of the Ostrava-Karviná Coalfields (Upper Silesian Coal Basin). Verification of the stress field response to stresses induced by different geological or mining factors was the main aim of the research project. Stress change monitoring in the region of the advanced longwall was carried out using seven stress probes. In all, seven boreholes were instrumented with compact conical ended borehole monitoring (CCBM) probes for continuous stress monitoring of the stress–strain changes due to mining and the destress blasting effect. Compact conical-ended borehole overcoring (CCBO) and CCBM probe installation were carried out before the start of the longwall mining. Data of the stress changes in all seven probes were recorded weekly and, after the longwall advanced, daily. Analysis of the stress changes was based on the idea of original stress distribution, which is based on long-term experiences in rock mass behavior in similar geological and mining conditions. For all probes, the magnitude of stress changes and principal axis direction changes were investigated. Analysis results to date indicate that stress changes ahead of the longwall face present not only the changes of stress magnitude, but the rotation of the axes of the stress components as well. Rotations of the principal axes emerged as very important factors of the stress tensor changes and their influence on rock mass deformation and stability of the workings. In addition, results show that the vertical to horizontal stress component ratio converges to 1 and in many cases horizontal stresses are higher than vertical ones. This of course relates to the impact of mine-induced stresses. This knowledge is basic for the purpose of prevention of rock burst because the actual stress state is fundamental to its proper and operative planning.
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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 | 0.001 | 0.001 |
| 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) | 0.001 | 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".