2.6.1. Mohr-Coulomb Failure Criterion

Try these first

1. 1.

   What is the Mohr-Coulomb failure criterion used for?

   Hint

   Think about what soil stability means in construction.

2. 2.

   Define cohesion in soil mechanics.

   Hint

   Consider what happens to sand versus clay.

3. 3.

   What parameters does the Mohr-Coulomb criterion depend on?

   • Only cohesion
   • Cohesion and angle of internal friction
   • Only normal stress

   Hint

   Look back at the equation we discussed.

4. 4.

   True or False: Cohesion is a property that varies significantly between different types of soils.

   • True
   • False

   Hint

   Recall the examples of cohesive soils like clay versus granular soils.

5. 5.

   A geotechnical engineer conducts a triaxial test on a soil sample that shows a cohesion of 15 kPa and a friction angle of 25°. Calculate the shear strength when the normal stress is 80 kPa.

   Hint

   Work through the equation step-by-step.

6. 6.

   A construction site on sandy soil has been found inadequate for supporting a foundation based on Mohr-Coulomb failure criteria. Discuss what soil properties might be problematic and suggest solutions.

   Hint

   Consider how different types of soil interact under pressure.