GATE 2017 CE (CE1) – Question 60

Geotechnical Engineering · Shear strength, Mohr circle, stress-strain characteristics, stress paths · 2 marks · Numerical answer

A consolidated-undrained triaxial compression test on normally consolidated clay has confining pressure 100 kPa, deviator stress at failure 80 kPa and pore-water pressure at failure 50 kPa. Find effective internal-friction angle in degrees, to one decimal place.

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: 25.5 to 27.0

Explanation

Total minor principal stress is 100 kPa and total major stress is $100+80=180$ kPa. Subtract pore pressure to get $\sigma_3\prime=50$ kPa and $\sigma_1\prime=130$ kPa. Normally consolidated clay is treated as having zero effective cohesion. Therefore $\sin\phi\prime=(\sigma_1\prime-\sigma_3\prime)/(\sigma_1\prime+\sigma_3\prime)=80/180=4/9$. Hence $\phi\prime=26.39^\circ$, or 26.4°.

More Shear strength, Mohr circle, stress-strain characteristics, stress paths questions

GATE 2025 CE (CE1) Q17 – The results of a consolidated drained triaxial test on a normally consolidated clay are…
GATE 2025 CE (CE2) Q47 – In the context of shear strength of soil, which of the following statements is/are…
GATE 2024 CE (CE1) Q46 – Which of the following statement(s) is/are CORRECT?
GATE 2024 CE (CE1) Q55 – A soil sample was consolidated at a cell pressure of 20 kPa and a back pressure of 10 kPa…
GATE 2024 CE (CE2) Q23 – Which one of the following saturated fine-grained soils can attain a negative Skempton's…
GATE 2024 CE (CE2) Q55 – A drained triaxial test was conducted on a saturated sand specimen using a stress-path…

All Shear strength, Mohr circle, stress-strain characteristics, stress paths questions →