UNDER CONSTRUCTION

It is not practical or a good use of an engineer's time to carry out long stability calculations on each modification of a slope. The following charts show a range of stability characteristics for slopes with various soil properties and shapes.

__Taylor's Charts:__

(Taylor's 1st chart to be inserted)

(2nd Taylor's Chart be inserted)

__Spencer's Charts:__

These include the effects of porewater
pressure. The charts are broadly similar to Taylor's Charts, but introduce
the parameter r_{u}, the porewater pressure ratio.

Each of the charts is calculated
for a single r_{u} value. In a slope, r_{u} will vary at
different points but we use a mean value for simplification. As the variance
isn't large, this is not an over-simplification

Spencer chose to use r_{u}
= 0, 0.25, 0.50.

We estimate a FoS for the slope
in question using each individual chart, and then interpolate for the actual
r_{u} value for the slope.

(Spencer's Charts to be inserted)