9.5. Examples

Try these first

1. 1.

   Define effective stress.

   Hint

   Think about the forces acting on soil.

2. 2.

   What does the hydraulic gradient represent?

   Hint

   Remember it indicates water flow direction.

3. 3.

   What happens to effective stress during upward water flow?

   • Increases
   • Decreases
   • Remains constant

   Hint

   Think about what upward flow does to soil particles.

4. 4.

   True or False: The effective stress increases when the pore water pressure rises while total stress remains unchanged.

   • True
   • False

   Hint

   Recall how effective stress is calculated.

5. 5.

   A soil layer has a total stress of 30 T at a depth of 10 m and a pore water pressure of 15 T. What is the effective stress?

   Hint

   Apply the effective stress formula.

6. 6.

   A construction site experiences a rise in pore water pressure of 5 T while total stress remains constant. What happens to effective stress?

   Hint

   Think about changes in pore water pressure affecting stability.