9.2. Hydraulic gradient

Try these first

1. 1.

   What is the hydraulic gradient?

   Hint

   Think about how water pressure changes over distance.

2. 2.

   Define effective stress.

   Hint

   Try to remember the formula!

3. 3.

   What does the hydraulic gradient represent?

   • Change in height
   • Change in potential energy
   • Change in hydraulic head over distance

   Hint

   It's related to water's drive through soil.

4. 4.

   True or False: A rise in the water table always increases effective stress.

   • True
   • False

   Hint

   Think about how total stress and pore pressure interact.

5. 5.

   A soil column has a total stress of 50 kPa at a depth below a rising water table. If the pore water pressure is calculated at that depth to be 20 kPa, what is the effective stress?

   Hint

   Use the effective stress equation to solve.

6. 6.

   Consider an upward water flow scenario with a hydraulic gradient approaching 1. What implications would this have on the stability of a sand layer?

   Hint

   Think about how it impacts weight support.