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A rock mass rating system provides a method of incorporating some of the complex mechanics of actual rocks into engineering design. Moreover, the system was the first to enable estimation of rock mass properties, such as the modulus of deformation, in addition to providing tunnel support guidelines and the stand-up time of underground excavations.
The Geological Strength Index (GSI) system, proposed in 1994 by Evert Hoek, is used for the estimation of the rock mass strength and the rock mass deformation modulus.. The GSI system concentrates on the description of two factors, rock structure and block surface conditions.
In geotechnical engineering, rock mass plasticity is the study of the response of rocks to loads beyond the elastic limit. Historically, conventional wisdom has it that rock is brittle and fails by fracture , while plasticity (irreversible deformation without fracture) is identified with ductile materials such as metals .
The objectives of rock mass classifications are (after Bieniawski 1989): Identify the most significant parameters influencing the behaviour of a rock mass. Divide a particular rock mass formulation into groups of similar behaviour – rock mass classes of varying quality. Provide a basis of understanding the characteristics of each rock mass class
The use of rock has had a huge impact on the cultural and technological development of the human race. Rock has been used by humans and other hominids for at least 2.5 million years. [22] Lithic technology marks some of the oldest and continuously used technologies. The mining of rock for its metal content has been one of the most important ...
A rock mass with a high RMR before the adjustment factors are applied has a high reinforcement potential, and can be reinforced by, for example, rock bolts, whatever the MRMR value might be after excavation. Contrariwise, rock bolts are not a suitable reinforcement for a rock mass with a low RMR (i.e. has a low reinforcement potential).
Slope mass rating (SMR) is a rock mass classification scheme developed by Manuel Romana [1] [2] [3] to describe the strength of an individual rock outcrop or slope. The system is founded upon the more widely used RMR scheme, [4] which is modified with quantitative guidelines to the rate the influence of adverse joint orientations (e.g. joints dipping steeply out of the slope).
In geology, size strength classification is a two-parameter rock classification based on the strength of intact rock and the spacing of discontinuities in the rock mass. It was developed by Louis and Franklin (1970–75). The size-strength approach to rock mass characterisation has been found helpful in various mining and civil engineering ...