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If so, what would it be its official name? it might have another name than Torsion test because I googled it and nothing was found. pdta: I know there is a torsion test for metals , but that is not what I am looking for. thank you.

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  • $\begingroup$ Are you asking for fun or why does the torsional properties of rock matter to you? There may be a specific test or property that is more applicable. $\endgroup$
    – hazzey
    May 7, 2017 at 3:15
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    $\begingroup$ It isn't a useful concept for most civil engineering. The shear strength of rock is limited by the shear strength between the individual rocks, not the strength of a single solid rock. It is usually much smaller than the strength of the rock itself, and similar the limiting friction force between two rocks, which depends on the roughness of the surface, whether there is any water or other material at the interface, etc, etc, etc, - in other words, you can't measure a "single value" that applies to all situations. $\endgroup$
    – alephzero
    May 7, 2017 at 3:21

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I am unaware of a torsion test for rock. Shear, compression & tensile strength tests yes, but not torsion.

All the civil engineers, mining engineers and geotechnical engineers I have worked with over the years have used shear, compression and occasionally tensile strength of rock. No-one ever mentioned torsion strength.

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  • $\begingroup$ What would it be the most similar test ( given the kind of stress in torsion) for rocks.? $\endgroup$ May 7, 2017 at 14:46
  • $\begingroup$ I know about a ring shear test that involves torsion movement , but it is for soils as far as I know. $\endgroup$ May 7, 2017 at 14:51
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    $\begingroup$ The most similar test would be a shear test. I can't think of why a torsional load would ever by applied to a rock in civil engineering. Why would anybody want to make machine with a shaft that transmitted torsional loads out of rock, instead of metal? I suppose somebody might want to make a sculpture out of a single piece of rock and its shape would apply a torsional load to some part of it, but sculptors don't usually bother to do stress analysis! $\endgroup$
    – alephzero
    May 7, 2017 at 16:36
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    $\begingroup$ Torsion stress is direct descendant of shearing stress; knowing shearing strength, and geometry you can easily calculate torsion strength. $\endgroup$
    – SF.
    Jun 6, 2017 at 12:38
  • $\begingroup$ The closest test I'm aware of would be the DSS (direct simple shear test). It's not run very often. It's not measuring torsion but you could calculate it. $\endgroup$ Jul 12, 2017 at 12:06

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