Gt Flashcards
Liquidity index
(W-Wp)/Wl-Wp
What is the liquidity index used for?
Scaling the neutral water content of a soil sample of the limits
What does a liquidity index value of I < 0 indicate?
Soil is in a solid state
What does a liquidity index value of 0 < I < 1 indicate?
Soil is in a semi-solid state
What does a liquidity index value of I > 1 indicate?
Soil is in a liquid state
How is the consistency index calculated?
Wp - Ws / Ip
What does the consistency index indicate?
The consistency (firmness) of a soil
What is the relationship between liquidity index and consistency index?
Liquidity index + Consistency index = 1.0
What does the flow index measure?
The rate at which a soil mass loses its shear strength with increase in water content
What is the formula for calculating the flow index?
Slope of the flow curve obtained between the number of blows and the water content
What does the toughness index measure?
Shear strength of a soil mass at its plastic limit
How is the toughness index calculated?
Plasticity index / Flow index
What is the activity of soils a measure of?
Water holding capacity of clayey soils
What is the relationship between activity and clay fraction?
Activity = Plasticity index / Percentage of clay fraction (minus 2u size)
What does an activity value of 0.75 < A < 1.25 indicate?
Soil is moderately active
What does an activity value of A > 4 indicate?
Soil is highly active
What does an activity value of A < 1 indicate?
Soil is least active
What is sensitivity in soil mechanics?
Weakening of a soil mass due to remoulding
How is sensitivity calculated?
Unconfined compressive strength of undisturbed clay / Unconfined compressive strength of remoulded clay
What does a relative density value indicate?
How a soil mass would behave under loads
What is the formula for relative density?
(Pmax - Pa) / (Pmax - Pmin) x 100
What does the parameter ‘Pa’ represent?
Density of water = 1 g/cm³
What is the behavior of a soil mass with a relative density of 1+e?
Indicates denseness of soil mass and void ratio
What type of clay mineral is kaolinite?
Insensitive
What type of clay mineral is montmorillonite?
Sensitive
True or False: The consistency index is greater than the liquidity index.
False
