Civil Engineering - UPSC Civil Service Exam Questions - Discussion


In a three-layered soil, water flows parallel to stratification. The thickness of the middle layer is twice that of top and bottom layer. The coefficient of permeability of middle layer (2K) is twice that of top and bottom layer (K). What is the average coefficient of permeability for this flow ?

[A]. K
[B]. 1.33 K
[C]. 1.5 K
[D]. 0.66 K

Answer: Option C


No answer description available for this question.

Saba said: (Oct 15, 2015)  
(k+2k+k)/4 = 1.33.

Chintu said: (Mar 21, 2017)  

How 4k/4 is 1.33?

Arya said: (May 2, 2017)  
Here, [K+2K+K]/3 = 1.33.

Himanshu Khandelwal said: (Jun 9, 2017)  
first layer=k(1)=k.
second layer=k(2)=2k(given).
third layer=k(3)=k.

first layer thickness=H.
second layer thichness=2H.
third layer thickness=H.

Average(k) = k * H+2k*2H+k*H/H+2H+H=1.5k.

Darshan said: (Jan 18, 2018)  
Correct @Himanshu.

Manjunath Reddy said: (Aug 13, 2021)  
Yes, you are correct @imanshu Khandelwal.

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