The use of densities or density ratios in specifications

From an engineering perspective, the specification of the density of a material should be based on the future use of the fill. The relative void ratio or relative porosity (also called relative density) is often used to describe sand deposits. Correlations have been developed relating the relative density to the angle of internal friction, liquefaction potential, etc. 

Some manuals present guidelines for the relative void ratio or relative porosity. These values can be used as a guideline in the preliminary design of a hydraulic fill. It should be kept in mind that the relative density is an indirect way of defining the strength (see Section 8.3). The required relative density of non-cohesive soils in hydraulic fills depends on the type of utilisation, which is laid down in the functional requirements. 

Storage areas Traffic areas Structure areas 

Eurocode 7 geotechnical design mentions the following note concerning the relative density  

Structural fills on which foundations are built shall be made with suitable materials for which an appropriate density, a 100% Proctor density (2.5 kg rammer, height of fall 0.3 m) as an average and a 97% Proctor density as a lower limit shall be assured and the risk of collapse and excessive differential settlements shall be prevented. 

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Definition of key parameters 8.3.2 Density ratios R3.3 The use of densities or density ratios in specifications ... 

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