Basics of Soil Mechanics- Geostatic Earth Pressure

Question 1

What is a homogenous soil deposit?

Answer 1

A soil deposit with constant unit weight

Question 2

When do we refer to vertical normal stress in terms of foundations?

Answer 2

Settlement of foundation

Question 3

For a sample of dry soil, what is the pore water pressure and what is the vertical normal stress?

Answer 3

• u = 0
• σ = σ’ = γz

γ = unit weight of soil

z = Depth of the point of interest

Question 4

For saturated soils what will the pore water pressure, the vertical normal stress and effective stress be?

Answer 4

• u = γ_wz

γ_{w = Unit weight of water}

_{z= Depth of interest}

• σ = γ_satz

γ_{sat = Saturated unit weight of soil}

• σ’ = σ - u = (γ_{sat -} γ_{w)z =} γ’z

Question 5

What will u, σ and σ’ be when the groundwater table is at a certain depth below ground level?

Answer 5

• For 0

u = 0

σ = σ’ = γz

• For z>D

u = γ_w(z-D)

σ’ = γD + γ’(z-D)

Question 6

How do we obtain effective stress when we have a layered soil sample?

Answer 6