Factors affecting compaction of soil

Compaction of soil is affected by these factors: Water content, compaction effort and type of soil

APSEd Courses

Simple, Quick & Easy

Hey, I'm Aditya. Do you want to learn concepts easily?  
 

Learn with APSEd and score high!

  • Video Lectures & Study Material

  • Practice Questions & Mock Tests

  • Formula Cards & Assessment Tests

  • Exclusive Doubt Support

What are the factors affecting compaction of soil?

• Water Content
• Compaction Effort
• Type of soil

Water Content

At lower water content
• Vander Waal forces between two clay particles exist
• Adsorbed water layer around the clay particles is not fully developed
• Net force between the particles is attraction so flocculated structure would form, so more voids so mess density

At higher water content
• Net force between the particles become repulsive
• Dispersive structure would form
• Void ratio decreases as the particles arranged in a particular manner

If we further increase the water content the place occupied by the soil particles will be replaced by water. Unit weight of water is less than the unit weight of solids, hence dry unit weight keeps decreasing.

Compaction Effort

Increase in the compactive effort increases the density on the dry of optimum where as the increase on the wet side of optimum is not that significant

10.png

Type of soil

In the case of sands, when some water is added then due to capillary tension, even if we give the compactive effort the particles are not moving closer.

This tension would be maximum when the water content is 4-5% where the dry unit weight is minimum at that time. If we further increase the water content capillary effect would be reduced and the water will start entering into the voids.

Then sand particles would move freely in to the spaces and occupy the better alignment, after which the dry unit weight starts increasing but in later stages like in previous cases the dry unit weight starts reducing again (See image)

Summary Points

• Compaction is affected by: Water content, compaction effort and type of soil
• At lower water content - flocculated structure would form
• At higher water content - dispersive structure would form
• Increase in the compactive effort increases the density on the dry of optimum where as the increase on the wet side of optimum is not that significant
• In sand, when some water is added then due to capillary tension, even if we give the compactive effort the particles will not move closer.

FREE career guidance

Talk to the founders! Only for first few users