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Questions and Answers
What is the primary basis for soil classification in engineering?
Which method is used for particle sizes larger than 0.075 mm in diameter?
What does the textural classification of soil primarily assess?
Which component is NOT part of the grain size classification in soil?
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What is the purpose of sieve analysis in soil classification?
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What is the percent passing for the 80 mm sieve?
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Which coefficient is used to assess soil gradation characteristics?
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What is the effective size (D10) in sieve analysis indicative of?
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What does the term 'C_c' denote in particle-size distribution?
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Which mass retained corresponds to the 20 mm sieve size?
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What is the significance of the Uniformity Coefficient (Cu)?
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Which value represents the cumulative mass retained after the 200 mm sieve?
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What does the suitability number (SN) evaluate?
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What particle size has a mass retained of 149 grams?
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For a sample with 797 grams total mass, what mass was retained for the 4 mm sieve?
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What is the effective size, D10, from the particle-size distribution data?
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Which diameter corresponds to the cumulative mass retained of 210 grams?
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What cumulative mass retained is associated with a diameter of 8 mm?
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What is the uniformity coefficient, Cu, calculated using the provided sorting coefficient?
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What cumulative percent passing corresponds to a diameter of 40 mm?
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What is the diameter where 10% finer is noted?
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Which of the following is the mass retained for a 100 mm sieve?
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At a diameter of 60 mm, what is the cumulative mass retained?
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What is the total mass retained across all sieves listed?
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Which diameter corresponds to a percent passing of 1.51%?
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Study Notes
Soil Classification Overview
- Soil classification groups soils based on similar characteristics and behavior, crucial for engineering applications.
- Mechanical properties such as permeability, stiffness, and strength are primary classification criteria.
Textural Classification
- Based on particle-size distribution: gravel, sand, silt, and clay proportions influence soil texture.
- Two main classification systems: USDA (United States Department of Agriculture) and MIT (Massachusetts Institute of Technology) for texture; AASHTO (American Association of State Highway and Transportation Officials) and USCS (Unified Soil Classification System) for engineering behaviors.
Grain Size Classification
- Mechanical analysis determines size ranges of soil particles, expressed as a percentage of total dry weight.
- Sieve Analysis: used for particles larger than 0.075 mm.
- Hydrometer Analysis: for particles smaller than 0.075 mm.
Sieve Analysis Method
- Involves passing soil through sieves of decreasing mesh size.
- Measures retained mass on each sieve to determine particle-size distribution.
Particle-Size Distribution
- Information is recorded in a table listing sieve diameters, mass retained, cumulative mass, and percent passing.
- Effective size (D10): diameter at which 10% of the soil particles are smaller, indicative of hydraulic conductivity.
Uniformity Coefficient (Cu)
- Calculated as Cu = D60 / D10, providing a measure of soil gradation.
- Higher values indicate a wider range of particle sizes.
Coefficient of Gradation (Cc) and Sorting Coefficient (So)
- Cc = (D30^2) / (D60 * D10) assesses the curve of the particle-size distribution.
- So = D75 / D25 gauges sorting quality of the soil.
Suitability Number (SN) Calculation
- SN equation accounts for effective sizes at various percentiles (D10, D20, D30, D50, D60, D75).
- Used to evaluate soil's overall suitability for different engineering applications.
Example of Particle-Size Distribution
- Sample data illustrates the mass retained on various sieves, cumulative mass, and percent finer for evaluation.
- Logarithmic interpolation enables precise assessments of particle sizes at specific percentiles.
Summary of Effective Sizes
- D10 = 0.163 mm, D30 = 0.219 mm, D50 = 0.351 mm, D60 = 0.506 mm, D75 = 0.927 mm.
- Effective size and uniformity help in understanding drainage and structural capabilities of the soil type.
Practical Applications
- Soil classification is vital in construction, land development, and environmental engineering, influencing material selection and design approaches.
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Description
Test your knowledge on soil classification, exploring its significance in engineering. Learn about textural classification systems and grain size analysis methods. This quiz covers both mechanical properties and texture classifications critical for understanding soil behavior.
