29.1.1. Modulus of sub-grade reaction

Try these first

1. 1.

   What is the modulus of sub-grade reaction?

   Hint

   Think about how soil reacts to weight.

2. 2.

   At what deflection value is the modulus of sub-grade reaction typically calculated?

   Hint

   It's a small value that represents slight bending.

3. 3.

   What does the modulus of sub-grade reaction measure?

   • The thickness of the slab
   • The pressure per deflection
   • The total weight of the pavement

   Hint

   Focus on what K represents in rigid pavement analysis.

4. 4.

   True or False: A higher modulus of sub-grade reaction allows for a thinner pavement.

   • True
   • False

   Hint

   Consider the relationship between support and thickness.

5. 5.

   In a pavement project, a soil survey indicates a sub-grade with a modulus of 50 kg/cm³. If a standard load of 10,000 kg is applied at a deflection of 0.2 cm, calculate the pressure applied and discuss the implications on pavement design.

   Hint

   Break down the formula.

6. 6.

   Analyze a situation where increasing the modulus from 30 kg/cm³ to 60 kg/cm³ allows for a thinner slab. If the original design was 20 cm thick, how much could this thickness be reduced while maintaining structural integrity?

   Hint

   Think about the balance of support and deflection limits.