Question

Consider the following statements regarding vibratory rollers:

(i) Vibratory rollers are used for compacting granular soils and pavement layers with granular materials.

(ii) Vibratory rollers are used for compacting non-plastic silts and fine sands.

(iii) In vibratory rollers, compaction is effected due to both the dynamic effect of the vibratory force and also the static weight of the roller.

Which of the above statement(s) is/are correct?

1. (i) and (ii)
2. (i) and (iii)
3. (ii) and (iii)
4. (i) only

Answer 1

Correct Answer - Option 2 : (i) and (iii)

Explanation:

Vibrating Compactors:

(i) Vibration creates impact forces, and these forces result in greater compacting power than an equivalent static load.

(ii) The impact forces are higher than the static forces because the vibrating drum converts potential energy into kinetic energy.

(iii) Certain types of soils such as sand, gravel, and relatively large shot rock respond quite well to compaction produced by combination of pressure and vibration.

(iv) When these material are vibrated, the particles shift their positions and come more closely with adjacent particles to increases the density of the material.

(v) The impacts imparted by the vibrations produce pressure waves that set the soil particles in motion, producing compaction.

 (i) The sheep foot roller is suitable for compacting all fine-grained materials (clay, silt etc.), but is generally not suitable for use on cohesionless granular materials.