Analysis, design and construction - Practical Engineering Geology - page 279

Box 6-6 Slopey, Slopey, Slopey (1982)

Figure B6-6.1 Chung Hom Kok, Hong Kong.

- sung (and danced if you wish) to the tune of the Hokey-Cokey.

You put your phi value in
You take your c' value out
You add a bit of suction
And you shake it all about
You do the old Janb u 2 a nd you turn around
That

' '

s what it s all about.

Chorus:
Oh slopey, slopey, slopey
Oh slopey, slopey, slopey
Oh slopey, slopey, slopey
It s so easy

One - point - four 3 !
Written and sung by the GCO Cabaret Stars, 1982
2 Janbu is the author of a commonly used limit equilibriummethod of slices for calculating Factors of Safety
of slopes and can be applied to non-circular surfaces. There are two forms: a routine method and a rigorous
method (Janbu, 1973). Lumsdaine &Tang (1982) carried out an exercise comparing results of calculations
by six Government Of

'

ces and 36 others and found a very high proportion of analytical errors and lack of
documentation, which of course is over and above any uncertainty in ground model, parameters adopted and
assumed groundwater conditions

either positive pore pressure or suction.
3 A Factor of Safety of 1.4 is generally regarded as an acceptable number to guard against failure in a high-
risk slope in Hong Kong (GCO, 1979; 1984).

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