Stepped Slip Surface
If the rock body contains a system of parallel discontinuous cracks inclined to the top face of a rock and the second system is indistinctive, then it is possible to consider a formation of a stepped (jagged) slip surface in the rock body. This surface can be introduced into the program using the Calla and Nicholas theory, which increases resistance on the stepped slip surface by Δτ.
normal stress acting in the direction normal to the slip surface
effective tensile strength of steps in the intact rock
part of the height ht associated with steps in the intact rock (not created by a secondary system of planes)
normal height of stepped wedge resting on an inclined plane of the principal system of discontinuity planes
Stepped slip surface
W.S. Dershowitz, H.H. Einstein - Characterizing rock joint geometry with joint system models Journal Rock Mechanics and Rock Engineering, Springer Wien ISSN 0723-2632 , Issue Volume 21, Number 1 / January, 1988 Pages 21-51.