Compaction of Soil and its Application

Overview:
Soil compaction is the process of applying mechanical energy to soil in order to remove air voids and increase its density. It is an important process in construction, as compacted soil provides better load-bearing capacity and stability. The compaction of soil is influenced by several factors such as moisture content, compaction effort, soil type, and compaction criteria. In certain applications, such as the construction of earth dams, different compaction criteria are used.

Compaction of Earth Core:
- The core of the earth, which is the central part of an earth dam, is compacted on the wet side of the optimum moisture content (OMC).
- The OMC is the moisture content at which the soil achieves maximum compaction and minimum voids. Compacting the earth core on the wet side of the OMC ensures better compaction and reduced permeability.
- The presence of moisture helps in the rearrangement of soil particles, resulting in better compaction and higher density.

Compaction of Homogeneous Dams:
- Homogeneous dams are compacted on the dry side of the OMC.
- The OMC for homogeneous dams is lower than that of the earth core. Compacting the soil on the dry side of the OMC helps to achieve a higher density and lower permeability.
- Dry compaction of homogeneous dams ensures that the moisture content is reduced to a level where the soil particles can be closely packed, resulting in improved strength and reduced seepage.

Governing Criteria:
- The compaction of the earth core is primarily governed by strength criteria.
- Strength criteria refer to the ability of the compacted soil to withstand external loads and maintain its stability.
- A higher density achieved through compaction helps in improving the strength of the core material, making it suitable for load-bearing purposes.

- The compaction of homogeneous dams is primarily governed by permeability criteria.
- Permeability criteria refer to the ability of the compacted soil to resist the flow of water through it.
- Compacting the soil on the dry side of the OMC helps to reduce the permeability of the soil, ensuring that there is minimal seepage through the dam.

Conclusion:
In summary, the compaction of the earth core is done on the wet side of the OMC, and it is governed by strength criteria. On the other hand, homogeneous dams are compacted on the dry side of the OMC, and their compaction is governed by permeability criteria. These different approaches to compaction ensure that the soil achieves the desired properties for its specific application, whether it is load-bearing or seepage control.