Question

How does the maximum dry unit weight play a role in designing a building?

Answer 1

The soil must be compacted to control the soil properties of earth constructions like dams, roads, etc. For this purpose a certain percentage of maximum dry unit weight must be achieved.

When water is added to soil,  it becomes easier for the particles to move past one another during the application of the compacting forces.

As the soil compacts  and  the gaps are reduced causing  the dry unit weight. It is also called dry density.The dry density is expressed in g/cm3 or t/m3.

In the beginning, as the moisture content in the soil increases the dry unit weight also increases.

 However, the increase cannot occur to an unspecified degree because the soil state comes near to zero air, clears line which gives the maximum dry unit weight for a given moisture content.

Answer 2

The optimum moisture content can be understood as the moisture content where you get maximum dry unit weight

Obtaining the precise amount of optimum moisture content (OMC) which gives the maximum dry unit weight is actually very important in building because it enable you to get the desired soil  strength and in some cases to reduce soil permeability.

It has a very important role in Geo-engineering and construction of dams, roads, landfills, foundations, airfields, hydraulic barriers and ground improvements.

Maximum dry unit enable maximization dry density, which increases compressibility, and also shearing strength.