Damaged rock zone study: a progress report
2008 (English)Report (Other academic)
The subject of the damaged rock zone around an underground excavation is very complex. Much of these complexities relate to the physics of the rock properties and the highly anisotropic conditions of the EDZ. In rock physics, for example, the sough after rock properties such as Young's modulus (E) and the strength parameters (óc, c, ö, etc) are tensor quantities - that is they have spatial characteristics (3-dimensional). So the question usually is: Is it sufficient to relate these parameters (which are tensors) to vector quantities such as velocity (which is one- dimensional)? Obviously, there is no mathematical relationship for this. The anisotropy within the EDZ also complicates any process that attempts to estimate the magnitude of these properties. A drill and blast excavation will result in complex fracture patterns (irregularly shaped, cracks ranging from micro to macro sizes, rock bridges, etc). All these complexities will affect the kinematics of rock deformation and strength characteristics. A large volume of publications is available on investigations into the excavation disturbed zone. However, much of these investigations have focussed on identifying the factors affecting the development and extent of this zone, with the primary goal of minimising or if possible to completely eliminate this zone, which though is not possible. A questionnaire on EDZ was send to various organisations and individuals. The responses revealed various views on the EDZ. The mining industry for example, sees the EDZ from two sides of the coin: (i) it can act as protective blanket (destressed zone) by pushing high stresses further into the rock and in doing so protect the excavation, (ii) it can also jeopardise the safety of personnel and equipment as well as resulting in increased support costs. For nuclear waste isolation group the EDZ will provide a flow path for nuclear radiation to reach the atmosphere. Further still, for the civil engineering, the problem is largely related to stability, and maintenance and operational costs. Each of these cases is unique since the requirements are different. Which parameters are important and which factors need attention will depend on the nature and purpose of the excavation.
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2008. , 172 p.
Technical report / Luleå University of Technology, ISSN 1402-1536 ; 2008:01
Civil engineering and architecture - Geoengineering and mining engineering
Samhällsbyggnadsteknik och arkitektur - Geoteknik och gruvteknik
Research subject Mining and Rock Engineering
IdentifiersURN: urn:nbn:se:ltu:diva-25514Local ID: f853f690-cfd8-11dc-9ad7-000ea68e967bOAI: oai:DiVA.org:ltu-25514DiVA: diva2:998567
Godkänd; 2008; 20080131 (ysko)2016-09-292016-09-29Bibliographically approved