Particle Size Analysis

Question 1

is the determination of the size range of particles present in the soil, expressed as a percentage of the total
dry weight.

Answer 1

Mechanical Analysis

Question 2

Two methods are generally used to find the particle-size distribution of soil:

Answer 2

(1) sieve analysis—for particle sizes larger than 0.075 mm in diameter and
(2) hydrometer analysis—for particle sizes smaller than 0.075 mm in diameter

Question 3

involves shaking the soil sample through a set of sieves with progressively smaller openings.

Answer 3

Sieve Analysis

Question 4

the diameter in the particle-size distribution curve corresponding to 10% finer. The effective size of granular
soil is a good measure of hydraulic conductivity and drainage through soil.

Answer 4

Effective Size

Question 5

Uniformity Coeffecient, Cu

Answer 5

Cu = D60/D10

Question 6

Coeffecient of Gradation Cc

Answer 6

Cc = D30^2 / (D60XD10)

Question 7

This parameter is another measure of uniformity and is generally encountered in geologic works and expressed as

Answer 7

Sorting Coefficient, S0

Question 8

Sorting Coefficient

Answer 8

S0 = sqrt (D75/D25)

Question 9

Massachusetts Institute of Technology (MIT)

Answer 9

Gravel >2
Sand 2 to 0.06
Silt 0.06 to 0.002
Clay <0.002

Question 10

US Department of Agriculture (USDA)

Answer 10

Gravel: >2
Sand: 2 to 0.05
Silt: 0.05 to 0.002
Clay: <0.002

Question 11

American Association of State Highway and Transportation Officials (AASHTO)

Answer 11

Gravel: 76.2 to 2
Sand: 2 to 0.075
Silt: 0.075 to 0.002
Clay: <0.002

Question 12

Unified Soil Classification System

Answer 12

Gravel: 76.2 to 4.75
Sand: 4.75 to 0.075
Fines (Silt and Clay): <0.075