Preliminary Study on Size Effect of Fractured Rock Mass with Sand Powder 3D Printing
Bibliographic record
Abstract
The size effect has a significant effect on the mechanical behavior of rock, thereby fundamentally influencing the stability of rock excavations. The main challenge associated with the experimental research on the size effect of fractured rock mass lies in the difficulty of specimen preparation to represent the influence of size and fracture on the mechanical behavior of the rock material. In order to preliminarily explore the feasibility of 3D printing technology in the field of rock mechanics, fractured rock specimens of different sizes and different fracture characteristics were produced using sand powder 3D printing technology. The uniaxial compression test was combined with the digital image correlation method (DIC) technology to study the influence of the size effect on the mechanical properties and deformation and failure of different fractured specimens. The research finds that: (1) The elastoplastic mechanical characteristics of the sand powder 3D printed specimens are similar to soft rock. Specimen size and fracture angle have significant effects on the mechanical properties of specimens. Under different fracture conditions, the uniaxial compressive strength (UCS) and Elasticity Modulus of sand powder 3D specimens should be decreased with the increase of the specimen size, and the size effect has different influences on the specimens with different fracture characteristics. (2) Under different fracture conditions, the crack initiation position and failure mode of specimens of various sizes are affected by the fracture inclination to varying degrees. (3) The size effect of fractured rock mass is closely related to the defect level inside the rock mass. The size effect originates from the heterogeneity inside the material. The research results verify the feasibility of applying sand powder 3D printing technology to study the size effect of fractured rock masses and provide an innovative test method for the size effect test study. Preliminary exploration of the size effect of fractured rock masses provides a powerful reference for related research in this field. The study proves the feasibility of applying sand powder 3D printing technology in similar rock mechanics tests and contributes to understanding the size effect of a fractured rock mass.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| 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 | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".