Select the correct option from the following statements related to shear strength of soil.
1.According to Mohr's theory, the failure envelope is a strength line.
2.The Mohr circle for unconfined compression test passes through the origin.

Correct option is C

Statement 1
According to Mohr’s theory, the failure envelope is a strength line.
In Mohr–Coulomb theory, the failure envelope represents the shear strength of soil and is given by:
τ = c+σtanϕ
This straight line is therefore called the strength line.
Statement 2
The Mohr circle for unconfined compression test passes through the origin.
In an unconfined compression test:
Minor principal stress
σ$$_3$$​ =0
Hence, the Mohr circle touches the origin on the normal stress axis.