Soil Classification and Grain Size Analysis

These flashcards focus on key terms and concepts relevant to soil classification and grain size analysis, aiding in studying for the exam on Soil Mechanics and Foundations.

Soil Classification

The process of organizing various soils according to their texture and properties.

Coarse-Grained Soil

Soils with larger particle sizes such as gravels and sands.

Fine-Grained Soil

Soils with smaller particle sizes such as silts and clays.

Grain Size

The diameter of individual soil particles, which can be categorized as coarse or fine.

Cohesionless Soils

Soils that do not adhere together, typically gravels and sands.

Cohesive Soils

Soils that tend to stick together, commonly silts and clays.

Grittiness Test

A method to classify soil by rubbing particles between fingers to determine texture.

Toughness Test

A test to assess clay content by kneading soil at or near the plastic limit.

Dry Strength Test

A method to determine soil's toughness by squeezing dry soil.

Hydrometer Analysis

A method to determine the particle size distribution of soil particles smaller than 0.075 mm.

Sieve Analysis

A technique used to separate soil particles based on size using a series of sieves.

Effective Size (D10)

The size at which 10% of the sample passes through; related to soil permeability.

Median Size (D50)

The particle size at which 50% of the soil sample is finer.

Coefficient of Uniformity (Cu)

A measure of the distribution of soil particle sizes, calculated as D60/D10.

Coefficient of Curvature (Cc)

A measure of the shape of grain size distribution curve, calculated as (D30)²/(D60*D10).

Well-Graded Soils

Soils with a wide range of particle sizes and higher Cu values.

Poorly Graded Soils

Soils lacking in variety of particle sizes, possibly with excess or deficiency of certain sizes.

Gap-Graded Soil

A type of poorly graded soil with certain particle sizes missing from the distribution.

Liquid Limit

The water content at which soil changes from a plastic to a liquid state.

Plastic Limit

The water content at which soil changes from a semi-solid to a plastic state.

Fineness Modulus (FM)

A measure of the fineness of aggregate calculated from the weighted average of sieve sizes.

Moisture Content

The amount of water contained in the soil, important for classification.

Plasticity Index

The range of moisture content over which a soil behaves plastically.

Shear Strength

The resistance of soil to shear stress, crucial for stability in engineering.

D10 Size

Particle diameter at which 10% of the sample's mass is smaller.

D60 Size

Particle diameter at which 60% of the sample's mass is smaller.

D30 Size

Particle diameter at which 30% of the sample's mass is smaller.

Hydrometer

A device used to measure the specific gravity of a suspension in soil analysis.

Particle Size Distribution

The proportion of different particle sizes in a soil sample.

Sieve Size

The measurement of openings in a sieve used during sedimentation and size analysis.

Soil Sample Weight

The total mass of the soil sample used for analysis.