Assessment of static liquefaction susceptibility of early age cemented paste backfills
Bibliographic record
Abstract
The use of cemented paste backfills (CPB) for stope filling as a tailings management method becomes almost indispensable for flexible, selective and safe underground mining operations. For CPB to play the role of secondary ground support, it must develop a certain uniaxial compressive strength (UCS). The UCS value is almost linearly proportional to the binder content used. However, the cost of the binder represents 8 to 16% of the operating costs of mining with cemented backfill. That is the reason why mining companies seek to reduce the binder cost by reducing the amount of binder in the CPB mixtures. Unfortunately, a reduction in the binder content could cause a significant decrease in CPB strength, particularly at early ages. Such a CPB strength reduction, under undrained conditions, may cause liquefaction-induced failures at early ages due to seismic shaking or static loading. Static liquefaction can occur if the CPB show contractive behaviour during undrained loading and if there is a triggering mechanism present. The triggering mechanism can be due to a rapid rate of CPB raising (overloading), changes in porewater pressure or reduction in lateral confinement. The objective of this study is to experimentally assess the static liquefaction susceptibility of CPB containing low percentages of HS Portland cement (1.5, 1.75 and 2 wt%) at early ages (3 and 7 days). For each cement percentage and both curing times, isotropically consolidated undrained (CIU) triaxial compression tests were performed. Preliminary results are provided and the conditions for static liquefaction triggering are either null effective minor stress or when the pore pressure ratio (ru) reaches or is close to unity (ru = u/’3 = 1). The results showed that only the CPB studied using 1.5 wt% cement reached the condition of initial static liquefaction temporarily (axial strain in the range 0.5–3.5%) before resisting against liquefaction development (dilative behaviour).
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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 | 0.001 |
| 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) | 0.000 | 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".