How is unit weight (wet) calculated?

• A. Weight total (mass total * g) / volume total
• B. Weight total x volume total
• C. Density of solid / density of water
• D. Mass of water / mass of solid

Answer: (A)

Unit weight (wet) is a fundamental concept in soil mechanics and geotechnical engineering, representing the weight of a unit volume of soil that includes both the solid particles and the water present in the soil. It is essential for various calculations related to soil behavior under loading and for understanding the moisture content of soils.

The calculation of unit weight (wet) is done by taking the total weight of the soil sample, which incorporates both the solid material and the water, and dividing it by the total volume of that sample. This is represented mathematically as:

Unit Weight (Wet) = Total Weight / Total Volume

When calculating total weight, it typically involves the mass of the material multiplied by the acceleration due to gravity (g), making the formula:

Unit Weight (Wet) = (Mass Total * g) / Volume Total

This formula accurately reflects the definition of unit weight and thus is the correct method for calculating the wet unit weight of soil. Understanding this calculation is crucial for geotechnical engineers when assessing the stability and behavior of soils under various conditions.