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Stability Analysis of Rock Slopes with Plane and Wedge Failure by Means of a Pocket Calculator


Although, in the investigation of the stability of a rock slope, the influence of several factors on the safety factor Fs has to be determined, it is not advantageous to use an explicit expression for Fs It can, in fact, be shown, that by dividing the forces into three groups, i.e. into the reactions (Ni, Si), the weight (W), and the resultant (R) of all the other forces acting in the system, a basic equation may be derived, in which the resultant R is on the left hand side of the equation. This basic formula has the following advantages:

  • it is valid both for plane and for wedge failure,
  • it permits several parameters to be comprised in two factors, and facilitates thereby, a quick evaluation of rock slope stability with the aid of a pocket calculator (or design charts),,
  • its application necessitates an understanding only of simple statical relationships, even in the cases of the wedge analysis, since the complicated algebraic operations may be formally separated,,
  • an extensive parameter study can be carried out very quickly, even for wedges, with the aid of a programmable pocket calculator.,


Kovári, Kalman and Fritz, Pit

Index Terms:

slope; stability; wedge; pocket calculator; rock; TunnelingGroup; Fritz, Pit; Kovari, Kalman


See also "Slope Stability with Plane, Wedge and Polygonal Sliding Surfaces" by Kovári and Fritz, 1978, and "Recent Developments in the Analysis and Monitoring of Rock Slopes" by Kovári and Fritz, 1984.

Further Information:

Date published: 1975