Question

A laboratory vane shear test apparatus is used to determine the shear strength of a clay sample and only one end of the vane takes part in shearing the soil. If $T=$ applied torque, $H=$ height of vane and $D=$ diameter of the vane, then shear strength of the clay is given by

• A. $\frac{T}{\pi D^2(H+\frac{D}{6})}$
• B. $\frac{T}{\pi D^2(\frac{H}{2}+\frac{D}{12})}$
• C. $\frac{T}{\pi D^2(H+\frac{D}{10})}$
• D. $\frac{T}{\pi D^2(H+\frac{D}{12})}$

Answer 1

The correct option is B $\frac{T}{\pi D^2(\frac{H}{2}+\frac{D}{12})}$

For vane shear test with one end in shearing
$\tau =\frac{T}{\pi D^2(\frac{H}{2}+\frac{D}{12})}$
When both ends take part in shearing
$\tau =\frac{T}{\pi D^2(\frac{H}{2}+\frac{D}{6})}$