Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

Discussion Forum : Soil Mechanics and Foundation Engineering - Section 5 (Q.No. 22)
22.
A structure is erected on an impervious clay whose thickness is 12 m. Drainage is possible both at upper and lower surfaces. Coefficient of consolidation is 0.015 cm2 per minute. For attaining 50% consolidation with a time factor 0.20, the number of days required
3233
3123
33331
3313
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
16 comments Page 1 of 2.

CH SWAMY said:   1 decade ago
Tv = Cv/t/H^2.

t = 0.2*12*12*100*100/(0.015*60*24) days = 13333.33 days.

Ramakrishna said:   1 decade ago
Tv = Cv*t/d^2 = (0.015*24*60)*0.2/(12*100)^2 = 333333.3333.

Bhargavi said:   1 decade ago
Tv = Cv*t/d^2 (here d is double drainage so d/2).

d = 12/2 = 6 m = 600 cm.
Cv = 0.015 cm^2/min.
Tv = 0.2 (time factor).

So, t = Tv*d^2/Cv.

= 0.2*(600)^2/0.015.
= 48*10^5 cm^2/min.

= 48*10^5/(24*60).
= 3333.33 days.
(2)

Abhay said:   10 years ago
Time factor T = Cv*t/H^2.

Where Cv = coeff. of consolidation cm^2/min.
t = time in min.
H = Thickness of soils sample.

Therefore,
t= T * H^2/Cv.

For double drainage H = 1200/2 = 600 cm.

t = 0.2 * (600^2)/(0.015) = 4800000 min.

t = 4800000/(24*60)days.

t = 3333.3333 days.
(3)

Apcivilian said:   9 years ago
Nice explanation @Bhargavi.

Santhu said:   8 years ago
According to me, 3333.33 days is correct.

Anisha said:   8 years ago
Can anyone explain the importance of 50 percentage consolidation mentioned in the question?

Arya said:   8 years ago
Agree @Anisha.

Garry said:   8 years ago
The correct ans is 3333.33 days.

Praful sl said:   8 years ago
Tv for 50% consolidation is 0.2 ie (pie/4*u^2) gives roughly 0.196~ 0.2 and the answer is 3333.33 days.


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