Shear Vane Tests

[Jameschen6]

It is noticed that the ASTM has formulas for:
A - the rectangular shape of (1) general and (2) H=2D
B - the tampered shape of ONLY H=2D

Unfortunately our vane is tampered with d=1 inch, D=2 inches, H=5 inches. Is there a formula for this Vane?

 

[dgillette]

Is this the Nilcon that is pointy on the bottom and flat on the top? If so, try

http://www.geotestusa.com.

They can probably provide it.

If not, it's not real hard to derive if you assume constant shear resistance Su over the whole failure surface. Integrate d(torque) = Su*radius*d(area). The cylinder part is just (pi D h)*D/2*Su because radius is constant = D/2. The rest, where the radius varies from zero to D/2, I can't do in my head.

On the other hand, assuming constant Su over the whole failure surface is probably not exactly right for peak strength (although I think it is correct for remolded). Nilcon might have a calibration factor that is a little different from what you get by that simplifying assumption.

 

[BigH]

I think that Bowles or Fang has the formulas for vanes - straight bottom or tipped. Don't have with me now or I'd post.