Effect of Different Modes of Lateral Boundary Constraints of the Direct Simple Shear (DSS) Device under Monotonic and Cyclic Shear Loading
Bibliographic record
Abstract
Abstract The direct simple shear (DSS) device is commonly employed to characterize the shear behavior of soil while representing a plane strain condition. In DSS devices that use cylindrical specimens, the plane strain condition is mimicked by constraining the lateral boundaries of the specimen against radial deformations during consolidation and shear loading. The current test standard recommends using either wire-reinforced rubber membrane or unreinforced rubber membrane enclosed with stacked rigid rings as suitable modes of confinement to constrain the lateral boundaries of DSS test specimens. Only limited studies have been performed to assess the effects arising because of these different ways of lateral boundary constraints on the test results, particularly when DSS tests are conducted at relatively higher vertical effective confining stress (σ′v0) levels. An experimental program was undertaken to study the effect of lateral boundary constraint mode during constant-volume monotonic and cyclic DSS tests. The constant-volume tests were conducted on reconstituted cylindrical DSS specimens prepared from a natural silty soil under the following three modes of lateral boundary constraints: (a) steel wire–reinforced rubber membrane only (Mode 1); (b) steel wire–reinforced rubber membrane enclosed with a set of thin, low-friction stacked rigid rings (Mode 2); and (c) unreinforced rubber membrane enclosed with a set of thin, low-friction stacked rigid rings (Mode 3). The findings from these tests, conducted on specimens initially consolidated to σ′v0 level up to 900 kPa, indicate that there was no significant difference in the shear response derived from the three cases of lateral boundary constraints. This suggests that the commonly used approach of simply confining the DSS test specimen using steel wire–reinforced rubber membrane alone (i.e., Mode 1) would be effective and adequate for use in monotonic and cyclic direct simple shear testing, for σ′v0 ≤ 900 kPa.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.000 |
| 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".