Compaction is any process by which the soil particles are artificially rearranged and packed together into a closer state ofcontact by any mechanical means so that the dry density of the soil is increased. Compaction is an entirely different process than consolidation. The following are the main differences between them:

1. Consolidation is a gradual process of reduction of volume under sustained, static loading where as compaction is a rapid process of reduction of volume by mechanical means such as rolling, tamping and vibration.
2. Consolidation causes a reduction in volume of a saturated soil due to squeezing out of water from the soil where as in compaction, the volume of a partially saturated soil decreases because of expulsion of air from the voids at the unaltered water content.
3. Consolidation is a process which occurs in nature when the saturated soil deposits are subjected to Static loads caused by the weight of the buildings and other structures. Howev....

Compaction is any process by which the soil particles are artificially rearranged and packed together into a closer state ofcontact by any mechanical means so that the dry density of the soil is increased. Compaction is an entirely different process than consolidation. The following are the main differences between them:

1. Consolidation is a gradual process of reduction of volume under sustained, static loading where as compaction is a rapid process of reduction of volume by mechanical means such as rolling, tamping and vibration.
2. Consolidation causes a reduction in volume of a saturated soil due to squeezing out of water from the soil where as in compaction, the volume of a partially saturated soil decreases because of expulsion of air from the voids at the unaltered water content.
3. Consolidation is a process which occurs in nature when the saturated soil deposits are subjected to Static loads caused by the weight of the buildings and other structures. However, compaction is an artificial process which is done to increase the density of the soil to improve its properties before it is put to any use.

Purposes:

• To increase shear strength and thus increase  bearing capacity.
• To reduce compressibility.
• To reduce permeability.
• To reduce potential of swelling and shrinkage.