A Unit Weight greater than zero must be specified for each material in the Define Material Properties dialog. Unit Weight of a material is expressed as a force per unit volume:
Metric units are kN / m3
Imperial units are lbs / ft3
Saturated Unit Weight
If a Water Table has been defined for a model, then you can define different Unit Weights above and below the Water Table for any material, as follows:
Select the Saturated Unit Weight checkbox and enter the SATURATED Unit Weight in this edit box. The Saturated Unit Weight will be used for material BELOW the Water Table.
The UNSATURATED Unit Weight is then entered in the first Unit Weight edit box. The Unsaturated Unit Weight will be used for material ABOVE the Water Table.
The Saturated Unit Weight option will ONLY be enabled if a Water Table exists.
NOTE: the Saturated Unit Weight is the saturated, bulk unit weight of the material, and should always be GREATER THAN the Unsaturated Unit Weight. The Saturated Unit Weight is NOT the buoyant unit weight of the material (i.e. the submerged unit weight under water) !!!