Drained Triaxial Test: $12\mathrm{.}8$ For a normally consolidated clay, the results of a drained

triaxial test are as follows

Chamber confining pressure $15l\frac{b}{i}{n}^2$

Deviator Stress at failure: $34l\frac{b}{i}{n}^2$

Draw Mohr's Circle and determine the soil friction angle ${}^{\text{'}}$