Question

The relationship between porosity n and void ratio e is given by _______

(a) 1+n= 1/(1+e)

(b) 1-n= 1/(1+e)

(c) n= 1/e

(d) n= 1/(1+e)

I had been asked this question in exam.

This key question is from Void Ratio, Porosity and Degree of Saturation topic in section Preliminary Definitions and Relationships of Geotechnical Engineering I

Answer 1

Right choice is (b) 1-n= 1/(1+e)

Easy explanation: The porosity n and void ratio e are given by,

e = Vv/Vs = n/(1+n)

n= Vv/V = e/(1+e)

n= e*(1-n)

∴ 1-n=1/(1+e).