Stability assessment of initial shotcrete lining using two-dimensional continuum numerical modelling
Bibliographic record
Abstract
The convergence–confinement method (CCM) is a simple tool for the preliminary design of ground support for circular excavations. The influence of excavation advance rate on the design of a support system is often ignored using the CCM. In this paper, a two-dimensional (2D) continuum numerical modelling approach for support design is introduced, which integrates the excavation advance rate into the CCM. The numerical simulations are carried out based on the results of a previously calibrated 2D finite element model of an instrumented section of a 10 m diameter shaft in an average-quality rock mass. First, the internal pressure reduction approach is used to simulate the three-dimensional shaft advance and to generate the ground reaction curve (GRC). The longitudinal displacement profile (LDP) is calculated using a semi-empirical approach. The LDP is then integrated with the GRC to determine the radial displacements corresponding to the locations of the shaft face and initial shotcrete liner. Knowing the shaft advance rate allows determination of the appropriate mechanical properties of early-age shotcrete based on empirical equations. The paper presents three approaches for analysing the stability of the shotcrete liner. The first approach is based on calculating the load Factor of Safety using support-capacity diagrams. In the second approach, the load Factor of Safety is calculated using the conventional CCM. In the third approach, the strain Factor of Safety is calculated by considering the plastic deformation of early-age shotcrete. The minimum allowable shotcrete thickness is then determined by calculating the load and strain Factors of Safety for different lining thicknesses. It is suggested that a combination of these approaches provides a deeper insight into the complex behaviour of early-age shotcrete lining during excavation advance compared with the conventional CCM.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".