Question

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

(a) σy= σy’-γw(h-he)

(b) σy= σy’+γw(h-he)

(c) σy= σy’/γw(h-he)

(d) σy= σy’*γw(h-he)

This question was posed to me by my school teacher while I was bunking the class.

The query is from Elasticity in chapter Elements of Elasticity of Geotechnical Engineering I

Answer 1

Right option is (b) σy= σy’+γw(h-he)

The explanation is: The total stress is equal to effective stress plus pore pressure. In y- direction, the normal stress is given by,

σy= σy’+u

u= γw(h-he)

where, h=total head at the point

he=elevation head

∴ σy= σy’+γw(h-he).