Comparative Analysis of Failure Envelopes Plotted by Different Standards
P. A. Tsoi, O. M. Usol’tseva
Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Rock strength failure envelope, Mohr’s circles, bulk compression, uniaxial compression, indirect tension, adhesion factor, internal friction angle
Abstract
The authors compare the strength characteristics of rocks, determined by standards GOST 21153.8-88 and ASTM D7012-04. The research involved 7 rock lithotypes (shale, diabase, metasomatic rock, marble, gneiss, quartzite, garnet) and bulk compression, uniaxial compression and indirect tension testing. Mohr’s circles and failure envelopes are plotted for each rock lithotype. The differences between the standards are found in terms of adhesion factors and internal friction angles: ASTM yields higher adhesion factors; internal friction angles vary depending on the rock type. The calculation formula allows predicting the uniaxial compression strength at an error of 10.5%. The failure envelopes are updated using the calculated data. The results highlight the significance of proper selection of a failure envelope plotting procedure in engineering design.
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