Laboratory studies on fracturing of low-permeability soils
Bibliographic record
Abstract
Hydraulic and pneumatic fracturing have been used to improve the effectiveness of most in situ remediation methods for contaminated sites underlain with unfavorable low-permeability soils. This paper presents results of a laboratory experimental investigation to characterize the mechanisms related to the initiation pressure and growth of fractures stimulated from vertical and horizontal wells. The mechanisms of fracture in low-permeability soils appeared to be of a tensile failure mechanism enhanced by the generation of pore pressure as the soil around the well was being sheared due to the radial-tangential stress difference imposed by the injected pressure. The impacts of initial fracture slots on fracture orientation and initiation pressure were also investigated. The test results have demonstrated that the presence of initial fracture slots could reduce the injection pressure required to initiate fracture in the well. The initial slot, however, did not necessarily control the orientation of the propagating fracture. The effect of imposed stresses in the soil was evaluated also and was found to influence the orientation and propagation of fracture. Smaller stress contrast favored multiple deviated fractures, whereas larger stress contrast favored distinct fractures.Key words: soil fracturing, laboratory test, low-permeability soil, fracture propagation.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".