A slope face is cut in granite with sheet joints dipping as shown.
A) Disregarding information about cohesion or friction along the joint surfaces, state why the cut is stable.
B) The roadway is to be widened which will require a slope face cut at a steeper angle. Assume zero cohesion along the joints. What engineering parameter must the joint surfaces possess (magnitude) to be stable on a steeper cut with no reinforcement.