Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding
Bibliographic record
Abstract
The effect of water on fracture toughness in various modes of mudstones was investigated using semicircular bend (SCB) specimens exposed to three-point bendings. Natural mudstone specimens are obtained using a special coring method and are then classified into three types (A, B, and C) corresponding to three directions/configurations of bedding planes (divider, arrester, and transverse). The results show that the Type A (divider configuration) specimens possess the largest fracture toughness value for all tested modes and same soaking time, whereas the Type C (transverse configuration) specimens have the smallest one. By increasing soaking time, the fracture toughness in all three modes decreases and the fracture mechanism changes from brittle failure to ductile failure. Among them, the Type C specimens have the highest degree of degradation for each soaking time period. Regarding the fracture modes, the degradation degree ofKIcis higher than that ofKIIcfor all three types of mudstone specimens. In addition,KIIc/KIcratio increases when soaking time is extended. Furthermore, in the initial and short soaking time stages, the experimentalKIIc/KIcresults are consistent with theoretical findings from modified MTS criterion. However, after being soaked 300 minutes for three types of specimens, the test curves deviate from the theoretical curves. Analogously, the mixed-mode I/II ratio ofKefftoKIcis consistent with the theoretical values in the initial stage when the degree of damage is low. With soaking time increasing, the experimental curve is gradually deviated from the theoretical curve. When soaking time reaches 300 minutes, the deviation is substantial. And the test data for the Type-A specimens are observed to provide better agreements with theoretical predictions by modified MTS criterion than those for the other two types of specimens.
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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 | 0.000 |
| 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 | 0.000 |
| 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".