Rock mass strength: a review
2003 (English)Report (Other academic)
The estimation of the rock mass strength is becoming more and more important as the mining depths increase in Swedish mines. A better understanding of the rock mass strength makes it possible to control stability problems in underground excavations. This review constitutes the first phase of a research project aimed at developing a suitable method to estimate the hard rock mass strength. One of the most common ways of determining the rock mass strength is by using a failure criterion. The existing rock mass failure criteria are stress dependent and often include one or several parameters that describe the rock mass properties. These parameters are usually based on classification or characterization systems. This report is a critical literature review on failure criteria for intact rock and rock masses and on classification/characterization systems. Those criteria and systems that are presented were selected based on the facts that they are published, well known, deemed suitable for underground excavations and/or instructive. Totally eleven failure criteria for intact rock, five for rock masses and nineteen classification/characterization systems are presented. To decide which systems and criteria that are applicable for hard rock masses, some limitations have been stated. The rock mass is assumed to be continuous, comprising of predominantly high-strength rock types with a uniaxial compressive strength of the intact rock in excess of 50 MPa and with a failure mechanism caused by compressive stresses. The limitations for further studies of the classification/characterization systems are that they should present a result that is related to the strength, give a numerical value, have been used after the first publication and be applicable to hard rock masses. Based on this study, it was concluded that the uniaxial compressive strength, block size and shape, joint strength and a scale factor are the most important parameters that should be used when estimating the rock mass strength. Based on these findings, selected systems and criteria were chosen for further studies. These include Rock Mass Rating (RMR), Rock Mass Strength (RMS), Mining Rock Mass Rating (MRMR), rock mass quality (Q- systemet), rock mass Number (N), Rock Mass index (RMi), Geological Strength Index (GSI) and Yudhbir, Sheorey and Hoek-Brown criterion.
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2003. , 92 p.
Technical report / Luleå University of Technology, ISSN 1402-1536 ; 2003:16
Research subject Mining and Rock Engineering
IdentifiersURN: urn:nbn:se:ltu:diva-22858Local ID: 49184040-78c8-11db-962b-000ea68e967bOAI: oai:DiVA.org:ltu-22858DiVA: diva2:995907
Godkänd; 2003; 20061120 (ysko)2016-09-292016-09-29Bibliographically approved