Question

A normally consolidated clay layer is 3 m thick (one way drainage). From the application of a given pressure, the total anticipated primary consolidation settlement will be 80 mm. A. What is the average degree of consolidation for the clay layer when the settlement is 25 mm? b. If the average value of Cv for the pressure range is 0. 002 cm²/sec, how long in days will it take for 50% settlement to occur? Tso= 0. 197. C. How long in days will it take for 50% consolidation to occur if the clay layer is drained at top and bottom?

Answer 1

A. The average degree of consolidation for the clay layer when the settlement is 25 mm is 25/80 = 0.313.

B. The time required for 50% consolidation to occur is given by the following equation:

t

50

​

=T

so

​

c

v

​

H

2

​

where:

t

50

​

is the time required for 50% consolidation to occur

T

so

​

is the time factor for 50% consolidation

H is the thickness of the clay layer

c

v

​

is the coefficient of consolidation

Substituting the given values into the equation, we get:

t

50

​

=0.197

0.002

3

2

​

=88.35 days

C. If the clay layer is drained at top and bottom, the time required for 50% consolidation to occur is given by the following equation:

t

50

​

=

4

1

​

T

so

​

c

v

​

H

2

​

Substituting the given values into the equation, we get:

t

50

​

=

4

1

​

0.197

0.002

3

2

​

=22.09 days

Step-by-step explanation: