theory relates the degree of consolidation and time

H

=

length of the drainage path, which in

subsequent to loading according to the following

the case of a specimen or stratum

draining from top and bottom would be

half the thickness of the specimen or

U(%) = f(T)

(5-3)

stratum

t

=

time corresponding to U

with

t

(5-4)

T=

cv

2

The relation between time factor and percent

H

consolidation for various boundary conditions is shown in

figure 5-5. If the values of cv and H are known for a

where

stratum of clay with given boundary conditions, the

U=

degree of consolidation or ratio of

theoretical curve can be replotted in the form of a

settlement that has occurred at a given

percent consolidation-time curve; if the ultimate

time to the ultimate settlement

settlement of the layer has been computed, the curve

T

=

dimensionless number called the time

can be further modified into a settlement-time curve. In

factor that depends upon loading and

order to compute, cv, it is necessary to transform the

boundary conditions

laboratory time-consolidation curve for the load

=

property of the soil known as the

cv

increment in question into the theoretical curve. A

coefficient of consolidation

method for ad- justing the laboratory curve in order to

compute the

U. S. Army Corps of Engineers

Figure 5-5. Time factors for various boundary conditions.

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