This keynote lecture addresses the problem of determining the mechanical stability of shallow circular cavities in cohesive-frictional ground (weak rocks and soils) assumed to obey a Mohr-Coulomb shear failure criterion. Methods traditionally used to analyze stability of shallow excavations are reviewed first. A method based on the application of limit analysis and shear strength reduction technique in full numerical analysis is chosen for evaluating stability conditions of shallow cavities. Application of a scalar factor of safety for shallow tunnels is introduced and dimensionless groups of variables controlling the stability of the openings are identified. The stability of shallow circular cavities in purely cohesive ground and in cohesive-frictional ground are discussed and observations of practical interest are highlighted. Comparison of stability results obtained with the proposed analytical equations, with full numerical analyses, and with approaches used by other authors in the published literature are discussed. The effect of water in the ground and inside the excavation on the obtained factor of safety is reviewed. Similarities of controlling groups of variables for the cases of shallow tunnels and slopes are highlighted.
|Original language||English (US)|
|Number of pages||5|
|Journal||Advances in Soil Mechanics and Geotechnical Engineering|
|State||Published - 2019|
Bibliographical notePublisher Copyright:
© 2019 The authors and IOS Press.
- CAES system
- Factor of Safety
- Finite Difference Method
- Limit Analysis
- Limit Equilibrium
- Shear Strength Reduction Technique
- Stability of shallow circular cavities