6.4.2. Group Symbols for Fine Soils

Try these first

1. 1.

   What percent of soil must be fine-grained to classify it under fine soils?

   Hint

   Think about the particle size.

2. 2.

   Name one property of clay particles.

   Hint

   Consider the physical shape of clay.

3. 3.

   What is the maximum particle size for fine-grained soils?

   • < 0.075 mm
   • > 0.075 mm
   • = 0.075 mm

   Hint

   Consider the definition of fine-grained soils.

4. 4.

   True or False: The liquidity index measures the degree of plasticity of a soil.

   • True
   • False

   Hint

   Remember what liquidity indices represent.

5. 5.

   A soil has a liquid limit of 45%, a plastic limit of 25%, and 70% clay content. Classify its activity and liquidity index.

   Hint

   Use the activity and liquidity index formulas.

6. 6.

   Given a soil with a plasticity index of 15% and 40% clay content, determine the classification and consistency.

   Hint

   Make sure to use the respective formulas for analysis.