Poisson's ratio of a soil sample is 0.4. Using ory of elasticity, estimated value of coefficient of lateral earth pressure at rest in same soil is:

Concept:

Lateral Earth Pressure:

When the soil is in elastic equilibrium (i.e. at rest) the ratio of horizontal to vertical stress is called the coefficient of earth pressure at rest.

• It is denoted by Ko = $\frac{{\sigma }_h}{{\sigma }_v}$

Also,

K_o = $\frac{\mu }{1-\mu }$

K_o = Lateral Earth Pressure at rest

μ = Poisson's ratio of earth

Calculation:

Given: μ = 0.4

∴ Ko = $\frac{0.4}{1-0.4}$ = 0.667 ≈ 0.7

Additional Information

• Earth Pressure at rest ⇒ Soil is still
• Active Earth Pressure ⇒ retaining wall moves away from the Soil
• Passive Earth Pressure ⇒ retaining wall moves towards the Soil