How To Calculate Safety Factor of Slope against Planar Failure | Formula and Hand calculations

Planar failure is common in rock mass; however, it cam also occur id soil material. This videos explains a simplified approach that gives the safety factor based on rock mass strength and rock slope inclination. The safety factor is defined as the ratio between the available strength (using the Mohr-Coulomb failure criterion) and the required strength (which is equal to the shear stress acting on the rock mass). This method can be effectively used to quickly estimate the stability of rock block that sits on the planar rock surface.

If you want to learn h how to use software to solve the same problems as in this example, then watch my other video here    • Tutorial 9: How to Estimate Safety Fa...  .
The problem is 'The height of the slope is 12 m. A failure plane is formed along a large joint surface that has cohesion of 10 kPa and the friction angle of 33 degrees. The plane has a dip of 42 degrees while the slope angle is 64 degrees. Considering the unit weight of 22 kN/m3 and dry conditions, determine the safety factor'.