Tutorial 6: Planar Failure in Rock Mass | Kinematic Analysis using Planes of Discontinuities

This tutorial will explain how to conduct a kinematic analysis of planar failure in rock mass. The data on dip and dip direction, slope face (45/135), and friction angle (35 degrees) is the same as the one used in the toppling analysis (Tutorial 5 • Tutorial 5: Kinematic ... ). For planar failure to occur, two conditions must be met: 1. rock mass/block must have somewhere to slide into - free space ('daylight'); 2. the joint friction must be less than the dip of joints.
Procedure:
1. Draw the slope face plane and tick the box 'Daylight'; all poles inside this circle (oval) will daylight and may lead to planar failure.
2. Draw a cone from the center of stereonet with a radius that is equal to the joint friction angle (i.e., 35 degrees). Select 'Cone' and use Trend=0, Plunge=90, Angle =35. All the poles out of this circle will have the inclination (i.e., dip) greater than 35 degrees.
3. Combine the pole points from Step 1 and Step 2 to define the area with the critical poles.
Also watch these videos:
Tutorial 4: How to Plot Great Circles and Poles of Rock Mass Discontinuities using Dips • Tutorial 4: How to Plo...
Tutorial 5: Kinematic Analysis of Toppling in Rock Mass | Step by Step Procedure • Tutorial 5: Kinematic ...