Modulus Ratio and Joint Factor Concepts to Predict Rock Mass Response

Ramamurthy, T and Latha, Madhavi G and Sitharam, T G (2017) Modulus Ratio and Joint Factor Concepts to Predict Rock Mass Response. In: ROCK MECHANICS AND ROCK ENGINEERING, 50 (2). pp. 353-366.

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Abstract

The commonly adopted rock mass classifications, namely RMR, Q and GSI, are used to estimate compressive strength and modulus of rock masses. These values have been examined as per modulus ratio concept, M (rj) , for their reliability. The design parameters adopted in some of the recent case studies based on these classifications indicate that the M (rj) values for rock masses are higher than those of the corresponding intact rocks. The joint factor, J (f), which is defined as a weakness coefficient in rock mass suggests that modulus ratio of rock mass (M (rj) ) has to be less than the modulus ratio of the corresponding intact rock (M (ri) ), on the basis of extensive experimental evidence. With joint factor, compressive strength, elastic modulus, cohesion and friction angle were estimated and applied in the analyses of a few cases. The predictions of deformations with this approach agreed well with the field measurements by adapting equivalent continuum approach. The modulus ratio concept is considered to present a unified classification for intact rocks and rock masses. Soil-rock boundary, standup time in under ground excavations and also penetration rate of TBM estimates have been linked to M (rj) .

Item Type:	Journal Article
Publication:	ROCK MECHANICS AND ROCK ENGINEERING
Additional Information:	Copy right for this article belongs to the SPRINGER WIEN, SACHSENPLATZ 4-6, PO BOX 89, A-1201 WIEN, AUSTRIA
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	03 Apr 2017 04:48
Last Modified:	03 Apr 2017 04:48
URI:	http://eprints.iisc.ac.in/id/eprint/56446

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