Study on impermeability of fly ash sand-based sealing wall under CO2 gas storage in strip backfilling goaf
Bibliographic record
Abstract
Using the remaining space of the gob after strip filling to carry out large-scale storage of CO2 gas is an ideal model to achieve green and low carbon construction in the large coal power base in northwest China. The impermeability of the goaf sealing wall to prevent the horizontal escape of CO2 gas is the key to the success or failure of this project. Taking the Zhundong II Mine in the Junggar Desertified Mining Area, Xinjiang, as the engineering background. Through high-pressure permeability experiments, phenolphthalein titration experiments, XRD diffraction experiments, SEM electron microscopy experiments and COMSOL numerical simulation, the 28-day permeation process of CO2 gas at 0.2, 0.4, 0.6, 0.8 and 1.0 MPa in the fly ash sand-based specimens with a mass ratio of 23 (windblown sand)∶11 (fly ash)∶2 (quicklime)∶1 (gypsum) was studied. The results show that: ① The permeation rate of CO2 gas in the specimens gradually decreases with the permeation time. The permeation depths at 28 days under the five pressures are 1.49, 2.40 , 3.20, 4.0 and 4.77 cm, respectively; ② The porosity and permeability of the fly ash sand-based specimens also show a negative exponential trend of decrease during the CO2 gas permeation process. The porosity and permeability at 28 days under the five pressures are 30.44% and 5.94×10−15 m2, 29.44% and 5.70×10−15 m2, 29.03% and 5.57×10−15 m2, 28.13% and 5.23×10−15 m2, and 27.02% and 4.95×10−15 m2, respectively; ③ During the permeation process of CO2 gas in the fly ash sand-based specimens, needle-like and flocculent CaCO3 crystals are formed, and the unit cell volume of CaCO3 is 1.15 times larger than that of Ca(OH)2, making the specimens more compact; ④ By dynamically assigning the permeability of the material before and after carbonization, it is simulated that the depth distances of CO2 gas in the fly ash sand-based sealing wall at 3 years under the five pressures are 0.606, 0.921, 1.172, 1.465 and 1.800 m, respectively. Finally, based on the engineering geological conditions of the Zhundong No.2 Mine coal-power base in Xinjiang's desertified mining area, this study focuses on the design of construction process parameters for sealing walls in goaf areas, providing reference for the green mining and low-carbon utilization of coal resources in the desertified mining areas in the northwest of China.
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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 | 0.001 |
| 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".