Higher Density and Lower Optimum Water Content in Soils

Higher density and lower optimum water content in soils are desirable qualities for various engineering applications, such as construction of foundations, embankments, and roadways. These qualities allow for better load-bearing capacity, stability, and reduced settlement. The question asks which type of soil achieves these qualities more easily.

1. Coarse Grained Soil
- Coarse grained soils include materials such as gravel and sand.
- These soils have larger particle sizes compared to fine grained soils.
- The larger particle size allows for better compaction and densification.
- Coarse grained soils generally have lower optimum water content.
- The larger void spaces between particles make it easier for water to drain out, resulting in lower water content.
- As a result, coarse grained soils can achieve higher densities with less water content.

2. Fine Grained Soil
- Fine grained soils include materials such as silt and clay.
- These soils have smaller particle sizes compared to coarse grained soils.
- The smaller particle size makes it more difficult for the soil particles to rearrange and settle into a denser configuration.
- Fine grained soils generally have higher optimum water content.
- The smaller void spaces between particles make it more difficult for water to drain out, resulting in higher water content.
- As a result, fine grained soils require more water to achieve higher densities.

3. Cohesionless Soil
- Cohesionless soils, such as sands and gravels, do not have cohesive properties.
- These soils rely on friction between particles for stability.
- Cohesionless soils can achieve higher densities due to the ability of particles to easily rearrange and compact.
- The absence of cohesive forces allows for better compaction with less water content.
- Therefore, cohesionless soils can achieve higher densities with lower water content.

4. Saturated Soil
- Saturated soils are completely filled with water, and the void spaces between particles are filled with water.
- Water in the void spaces hinders the particles from rearranging and settling into a denser configuration.
- Saturated soils generally have lower densities and higher water contents.
- Therefore, saturated soils do not achieve higher densities and lower water contents easily.

Conclusion
The answer to the question is option 'A' - Coarse grained soil. Coarse grained soils, such as gravel and sand, have larger particle sizes, allowing for better compaction and densification. They also have larger void spaces, which facilitate drainage and result in lower water content. Hence, coarse grained soils can achieve higher densities with less water content compared to fine grained soils, cohesionless soils, and saturated soils.