Nomenclature for Triaxial Test
Nomenclature for Triaxial Test
(OP)
I've heard some engineers and textbooks refer to triaxial tests as 'triaxial shear' tests. I have also heard the test referred to as 'triaxial'. I've also had several senior engineers attack me for using the phrase 'triaxial shear' because, as he put it, 'there is no shear in a triaxial test'.
Personally I don't see anything wrong with calling it a triaxial shear test. Obviously there must be some shear in the soil within the test, otherwise how on earth would you get shear strength parameters from it?
Personally I don't see anything wrong with calling it a triaxial shear test. Obviously there must be some shear in the soil within the test, otherwise how on earth would you get shear strength parameters from it?





RE: Nomenclature for Triaxial Test
The correct terminology is a triaxial shear test. Triaxial refers to the loading directions and shear refers to the failure mode/planes.
RE: Nomenclature for Triaxial Test
Regardless, this is all semantics and it's not like anyone would misunderstand you.
For what it's worth, I would go with 'triaxial test' purely for brevity: there's no point adding the word 'shear' since it adds nothing to the description besides extra letters.
RE: Nomenclature for Triaxial Test
Sometimes, you need to find better senior engineers to work with - ones that don't attack - ones that actually understand geotechnical engineering. As far as I'm concerned, it'll be unlikely that they will change their perspective, 'cause now they're dug in!
In case the subject returns back to you - yes, you can also derive other paramaters from the triaxial shear test. However, who'd order a triaxial strength test if you only are interested in one of the other parameters?
What do your senior engineers say about the direct shear test?
What do you senior engineers think about stress paths?
Have they offered you their copy of Bishop and Henkel?
f-d
ípapß gordo ainÆt no madre flaca!
RE: Nomenclature for Triaxial Test
RE: Nomenclature for Triaxial Test
Sure, the applied loads in a triaxial test are normal to a sample surface.
Your OP claims, 'there is no shear in a triaxial test'. {sic} But, there is. . . There's shear on the failure surface, which is not normal to the applied load (i.e., sigma 1 or sigma 3). The claim, "There's no shear in a triaxial compression test" is just so wrong, it almost doesn't matter what Morgenstern says. There is shear, it's measured, it's plotted and it's used to derive the friction angle, which is our nomenclature for stress-dependent shear strength.
Maybe I'm missing something?
f-d
ípapß gordo ainÆt no madre flaca!
RE: Nomenclature for Triaxial Test