Which one of the following statements is not correct regarding Taylor’s stability number ?
- ATaylor’s stability number N is defined as Cm / γH.
- BThe procedure is based on the Swedish method of slices.Correct
- CThe results are embodied in Taylor’s design charts which may be used for determining the factor of safety of a slope or for designing the height for a desired safety factor.
- DIt is an analytical approach.
Solution
Concept
Taylor's stability number and chart
Formula
Ns = cm / (γ H)
Step-by-step solution
1. Taylor's stability number is N = cm / (γ H), where cm is the mobilised cohesion. 2. Taylor developed the charts from the friction circle method (an analytical method), not from the method of slices. 3. So the statement linking it to the Swedish slice method is not correct.
Explanation
Taylor's charts give the stability number as a function of the slope angle and φ. They were developed with the friction-circle method for homogeneous slopes and can be used to find FS or the safe height.
Why the other options are wrong
Statements (a), (c) and (d) correctly describe the stability number and its charts.
Shortcut
Taylor = friction circle; Fellenius = slices.
Common mistake
Confusing Taylor's method with the Swedish slice method.
Correct answer: B) The procedure is based on the Swedish method of slices.