Design and Fabrication of End Platens for Acquisition of Small-Strain Piezoelectric Measurements During Large-Strain Triaxial Extension and Triaxial Compression Testing
Bibliographic record
Abstract
Abstract A triaxial testing device was integrated with piezoelectric transducers to measure small-strain (<10−3%) dynamic soil properties during large-strain (15 %) triaxial testing. To incorporate the technology into existing equipment, end platens were designed and fabricated to facilitate direct contact between the transducers and the soil specimen. The platens protected the sensitive electronics while providing a seal between the confining fluid and the pore fluid. Two types of transducers were incorporated into the apparatus, bender elements and bender disks, used to measure shear wave and compression wave velocities, respectively. The 3.81-cm (1.5-in.) diameter acrylic end platens were designed to house the transducers, a porous stone, and openings to facilitate pore fluid drainage and wiring for the transducers. The top platen included a vacuum attachment and piston mount that enabled triaxial compression and triaxial extension testing. Removable stainless steel inserts were designed and fabricated to house and secure the transducers. These stainless steel inserts were used to ground the apparatus and allowed for maintenance and, if necessary, replacement of individual transducers. To ensure that the transducers were not damaged when subjected to the pore fluid, the transducers were waterproofed. Accurate readings of shear wave and compression wave velocities were obtained via proper design, fabrication, calibration, and implementation of the integrated small-strain components. Accurate readings of axial deformation, shear stress, and confining stress were also obtained via proper design, fabrication, and implementation of the vacuum connection components. Calibration results, as obtained from tests on specimens of medium-dense, dry, Ottawa sand, are presented and discussed. The system time delay was determined to be 5.67 × 10−5 seconds for the bender elements and 3.50 × 10−5 seconds for the bender disks. Measured shear wave velocity values ranged between 178 and 251 m/s and the corresponding compression wave velocity values ranged between 291 and 451 m/s.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".