Design charts for the prediction of overbreak in circular excavations in bedded or foliated rocks
Abstrak
A simple method is outlined for the assessment of overbreak in raise bores and other circular excavations that specifically includes consideration of the spacing of discontinuities. The two-dimensional method is based on considerations of stress anisotropy implemented with a transversely isotropic continuum rather than by strength anisotropy; in fact, the rock strength is modelled as isotropic. The shear stiffness of discontinuities is stress dependent and this means that the method is statically indeterminate. A work-around is presented based on defining design sectors based on the orientation of the excavation faces relative to the orientation of the discontinuity set. When faces are parallel to the discontinuity set the rock mass is modelled as being transversely isotropic and for faces normal to the discontinuity the rock mass is modelled as isotropic. A brittle failure criterion incorporating damage initiation and a spalling limit allows the production of design charts that can be used as a complement to existing methods to identify potential hazards before excavation.
Penulis (1)
Ross Seedsman
Akses Cepat
- Tahun Terbit
- 2025
- Bahasa
- en
- Sumber Database
- CrossRef
- DOI
- 10.1177/25726668251314739
- Akses
- Open Access ✓