A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Overbreak and underbreak in underground openings Part 2: causes and implications
Summary The newly developed light sectioning method has been used to investigate some of the causes and costs of overbreak and underbreak. Investigations at the Aquamilpa Hydroelectric Project in Mexico have shown decreased overbreak and increased underbreak as a result of increased rock quality and decreased explosive energy. A new measure of explosive energy, the ‘perimeter powder factor’ (PPF), has been defined and shown to be useful in the context of tunnel-wall rock damage. Tentative results indicate that explosive energy (PPF) may be a more important factor in producing underbreak, whereas rock quality may be a greater factor in producing overbreak. A site-specific equation is given for predicting overbreak or underbreak as a function of rock quality and explosive energy, with an evaluation of the cost of underbreak and overbreak.
Overbreak and underbreak in underground openings Part 2: causes and implications
Summary The newly developed light sectioning method has been used to investigate some of the causes and costs of overbreak and underbreak. Investigations at the Aquamilpa Hydroelectric Project in Mexico have shown decreased overbreak and increased underbreak as a result of increased rock quality and decreased explosive energy. A new measure of explosive energy, the ‘perimeter powder factor’ (PPF), has been defined and shown to be useful in the context of tunnel-wall rock damage. Tentative results indicate that explosive energy (PPF) may be a more important factor in producing underbreak, whereas rock quality may be a greater factor in producing overbreak. A site-specific equation is given for predicting overbreak or underbreak as a function of rock quality and explosive energy, with an evaluation of the cost of underbreak and overbreak.
Overbreak and underbreak in underground openings Part 2: causes and implications
Ibarra, J. A. (author) / Maerz, N. H. (author) / Franklin, J. A. (author)
1996
Article (Journal)
English
Overbreak and underbreak in underground openings Part 2: causes and implications
| British Library Online Contents | 1996
Causes, impact and control of overbreak in underground excavations
Online Contents | 2005
Causes, impact and control of overbreak in underground excavations
| British Library Online Contents | 2005
Evaluating extent and causes of overbreak in tunnels
| Online Contents | 2009