Lacey's Silt Factor and Alluvial Soil

Lacey's Silt Factor is an empirical coefficient used in the design of open channels for the estimation of the sediment-carrying capacity of water flowing in the channel. It is defined as the ratio of the weight of silt that can be carried by a unit weight of the alluvial soil to the weight of sand that can be carried by the same unit weight of alluvial soil.

Alluvial soil is a type of soil that is deposited by the action of rivers, floods, and other natural phenomena. It is composed of different types of particles, including sand, silt, and clay. The composition of alluvial soil determines its properties, including its porosity, permeability, and shear strength.

Choosing the Right Alluvial Soil for Lacey's Silt Factor

To determine the correct alluvial soil for Lacey's Silt Factor, we need to consider the size of the particles in the soil. The size of the particles affects the sediment-carrying capacity of the water flowing in the channel.

The correct answer to the question is option 'B', which is medium bajri of size 1.3mm. This is because the size of the particles in medium bajri is closest to the size of the particles in silt. When the size of the particles in the alluvial soil is closer to the size of the particles in silt, the Lacey's Silt Factor is higher, which means that the sediment-carrying capacity of the water in the channel is also higher.

Conclusion

In summary, Lacey's Silt Factor is an important factor in the design of open channels. Alluvial soil is composed of different types of particles, including sand, silt, and clay. The correct alluvial soil for Lacey's Silt Factor depends on the size of the particles in the soil. The size of the particles affects the sediment-carrying capacity of the water flowing in the channel. The correct answer to the question is option 'B', which is medium bajri of size 1.3mm.