5.3.2.1. Effective Size and Uniformity Coefficient

Try these first

1. 1.

   What does D10 represent in soil classification?

   Hint

   Think about the significance of percentages in particle size.

2. 2.

   What is the purpose of the uniformity coefficient (Cu)?

   Hint

   Consider how grading might affect soil stability.

3. 3.

   What does effective size (D10) indicate?

   • Size at which 10% of soil is finer
   • Size at which 50% of soil is finer
   • Size at which 100% of soil is finer

   Hint

   Remember the number associated with D10.

4. 4.

   A uniform soil has a uniformity coefficient (Cu) less than 3. True or False?

   • True
   • False

   Hint

   Consider what qualities a well-graded soil would have compared to a uniform soil.

5. 5.

   Scenario: A soil sample has a D10 of 0.15 mm, D30 of 0.25 mm, and D60 of 0.45 mm. Calculate the uniformity coefficient (Cu) and classify the soil's grading.

   Hint

   Remember the formula for uniformity coefficient is Cu = D60/D10.

6. 6.

   Case Study: You are tasked with designing a foundation for a structure in a region with 90% silt. Predict how this uniform soil behavior might affect the construction.

   Hint

   Consider how silt behaves under load and its water retention capabilities.