What does kinematic analysis check?

Whether discontinuity geometry permits movement, ignoring forces

Which is the plane failure test?

Dip direction within 20° of slope and phi < psi_p < psi_f

Line plunge between phi and psi_f

What if a mode passes its test?

A stability calculation (factor of safety) is required

2068 Magh · 2 marks

Kinematic tests for failures

Short answer

Kinematic tests check if discontinuities permit block movement. Plane failure needs dip direction within ±20° of the slope and friction angle<plunge<face dip. Wedge failure requires the intersection plunging out with its plunge between friction angle and face dip. Oppling needs planes dipping steeply into the slope with dip≥90°–face dip+friction angle.

What are the kinematic tests for failures?

Kinematic analysis checks whether the geometry of the discontinuities permits a block to move out of a rock slope, without considering forces. It is done on a stereonet for each failure mode (Markland test and others).

Failure	Test (kinematic condition)
Plane	Dip direction of plane within $\pm 20^\circ$ of slope dip direction; $\phi < \psi_p < \psi_f$ (pole inside the daylight envelope, outside the friction circle)
Wedge	Line of intersection plunges out of the face; $\phi < \psi_i < \psi_f$ (intersection point between the slope great circle and the friction circle)
Toppling	Planes dip into the slope (dip direction about $180^\circ$ from the slope's, within $10^\circ$ to $30^\circ$ ); $\psi_p \geq 90^\circ - \psi_f + \phi$

If a mode passes its test, the slope is kinematically unstable for that mode and a stability calculation (factor of safety) is then required. If none passes, the slope is kinematically stable.

✓ Answer checked by Claude Opus 5.5 (high effort)

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