Question

For which of the following types of sand is the angle of internal fraction maximum?
1. Angular-grained dense sand
2. Angular-grained loose and
3. Round-grained loose sand
4. Round-grained dense sand

Answer 1

Correct Answer - Option 1 : Angular-grained dense sand

Concept:

Angle of internal fraction:

• The angle of internal friction is a physical property of earth materials or the slope of a linear representation of the shear strength of earth materials.
• The angle of repose is a representation of the angle of internal friction. However, it tends to be governed by grain shape such that the slopes of most piles of loose, dry grains of natural soil are in the range of 28° to 34°.

Explanation:

• Angle of internal fraction mainly depends upon the contact area of the grains.
• Higher the contact area higher the angle of internal friction.
• In angular-grained dense sand, Area will be more for angular than rounded grains. 
• Due to dense packing, the contact area will be more.
• Hence, the angle of internal friction is maximum for angular-grained dense sand.