The user is free to modify the contents of all 18
end user might use the program. By stating all
input parameters that are passed to the array set-
the other parameters, the end user is then able to
tings. The function RIGIDICE (settings) returns an
predict heave rate as a function of heave pressure
array that contains the eight calculated variables.
Owing to the number of input parameters, a
thorough sensitivity study of the program is very
time consuming. This study employed a quicker
approach in which the relative significance of the
various input parameters is obtained through a
simple scheme of sequentially varying one param-
eter at a time and noting the resulting effect on
the important calculated parameters. Each input
parameter is modified by 10% and the calculated
results noted. The initial reference value for each
parameter is obtained from past measurements for
one particular silty soil (Black and Miller 1985, 1990).
It is evident that the heaving pressure is of pri-
mary concern to the end user. The heaving pres-
sure is therefore the output parameter to be ex-
amined. In addition to examining how the heave
pressure alone changes with each parameter, the
heave rate and heave pressure behavior will be
examined as the other parameters are modified
one at a time. This approach is similar to how an
b. Lower limit of freezing, Wd.
a. Saturated water content, Wsat.
Figure 4. Changes in heave pressure vs. heave rate for changes in chosen input parameters.