Question

The normal stress in z-direction in terms of effective stress is given by __________

(a) σz= γw(h-he)

(b) σz= σz’

(c) σz= σz’+γw(h-he)

(d) σz= σz’-γw(h-he)

The question was posed to me by my college professor while I was bunking the class.

I need to ask this question from Elasticity topic in portion Elements of Elasticity of Geotechnical Engineering I

Answer 1

The correct choice is (c) σz= σz’+γw(h-he)

To explain I would say: The total stress is equal to effective stress plus pore pressure. In x- direction, the normal stress is given by,

σz= σz’+u

u= γw(h-he)

where, h=total head at the point

he=elevation head

∴ σz= σz’+γw(h-he).