Major principal stress in a soil is represented by the symbol
- Aσ1Correct
- Bσ2
- Cσ3
- Dσ4
Solution
Concept
Principal stresses are written σ1 (major), σ2 (intermediate) and σ3 (minor).
Formula
σ1 ≥ σ2 ≥ σ3
Step-by-step solution
1. Principal stresses are ordered by size. 2. σ1 is the major principal stress. 3. σ2 is the intermediate principal stress. 4. σ3 is the minor principal stress.
Explanation
The largest principal stress is called the major principal stress and is written σ1. In the triaxial test, σ1 is the axial stress and σ3 is the cell pressure.
Why the other options are wrong
B: s2 is the intermediate principal stress. C: s3 is the minor principal stress. D: There is no s4; only three principal stresses exist.
Shortcut
1 = largest, 3 = smallest.
Common mistake
Mixing up σ1 and σ3 in triaxial test problems.
Correct answer: A) σ1