Question

A cohesive soil has angle of shearing resistance and cohesive of ${20}^{\circ }$ and $35kN/m^2$ respectively. If a specimen of this soil is subjected to triaxial compression test, the total axial stress required for failure under a cell pressure of $150kN/m^2$ is kPa.

• A. 406
• B. 512
• C. 716
• D. 320

Answer 1

The correct option is A 406

Given : $\varphi ={20}^{\circ }$

$C=35kN/m^2$

${\sigma }_3=150kN/m^2$

${\alpha }_f=45+\frac{20}{2}$

$={55}^{\circ }$

${\sigma }_1={\sigma }_{3}ta{n}^2{\alpha }_f+2ctan{\alpha }_f$

${\sigma }_1=150\times ta{n}^2{55}^{\circ }+2\times 35\times tan{55}^{\circ }$

$\therefore {\sigma }_1=405.91kPa$

${\sigma }_1=406kPa$