Shear Strength MCQ with answer and solution

Concept

Correlation of φ with density index (relative density)

Step-by-step solution

1. For cohesionless soils φ increases with relative density (density index). 2. Empirical correlations (e.g. from SPT or Dr) are used to estimate φ.

Explanation

The angle of internal friction of sand is most reliably correlated with its density index (relative density). Particle size, roughness and gradation also influence φ but are not used directly for the estimate.

Shortcut

Sand: φ rises with relative density.

Common mistake

Choosing particle size.