Grain, Soil and Water Pressure: Soil Conditions with and without Groundwater Flashcards
1
Q
What is the effective stress impact on soil without groundwater?
A
Full weight of soil is carried by grains.
2
Q
What is the effective stress impact on soil with groundwater?
A
Water pressure reduces effective stress.
Formula: σ_v = σ_v’ + σ_w
3
Q
How is effective stress calculated with groundwater?
A
- Calculate total soil stress: σ_soil = h × γ_sat
- Calculate water pressure: σ_w = h_water × γ_water
- Determine effective stress: σ’ = σ_soil - σ_w
4
Q
Why does soil weight change below the groundwater table?
A
The saturated unit weight (γ_sat) is used because soil pores are filled with water.
