Plasticity Chart For Soil Mechanics

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SILT (M-SOIL), M, plots below A-line m and C may be combined as FINE SOIL, F. CLAY, C, plots above A-line I

SILT (M-SOIL), M, plots below A-line m and C may be combined as FINE SOIL, F. CLAY, C, plots above A-line I

Plasticity Chart Components
Liquid limit (percent) Fig. 1.7 Plasticity chart for the BSCS (after BS5930: 1981).

The main soil types are designated by capital letters:

G Gravel M Silt, M-soil

S Sand C Clay

F Fine soil, Fines Pt Peat

The classification 'F' is intended for use when there is difficulty in determining whether a soil is a silt or a clay.

Originally all soils that plotted below the A-line of the plasticity charts were classified as silts. The term 'M-soil' has been introduced to classify soils that plot below the A-line but have particle size distributions not wholly in the range of silt sizes.

Behind the letter designating the main soil type additional letters are added to further describe the soil and to denote its grading and plasticity. These letters are:

W Well graded L Low plasticity (wL<35%) P Poorly graded I Intermediate (35<wL<70) Pu Uniform H High plasticity (50 < wL < 70)

O Organic E Extremely high (wL>90%)

The letter O is applied at the end of the group symbol for a soil, no matter what type, if the soil has a significant amount of organic matter within it. Examples of the use of the symbols are set out below.

Soil description

Group symbol

Well graded silty SAND

+3 -4


  • Carl Curran
    How to draw aline chart in soil mechanics?
    3 years ago
  • brogan
    How to draw a plasticity chart?
    2 years ago
  • Sarah
    What can i make for soil mechanics chart?
    2 years ago
  • Joshua
    What is A line diagram in soil mechanics?
    2 years ago
  • Wegahta
    How to draw plasticity graph?
    2 years ago
  • Siiri
    How will you classify organic from plasticity chart?
    2 years ago
  • priamus
    What type of soil that is plot above the plasicity?
    1 year ago
  • helvi suorsa
    What type of soil that plot above a line in the plasticity chart?
    1 year ago
  • robin
    Which write or draw placity chart?
    1 year ago
  • leo
    How the plasticity chart is help in classifying the soils?
    1 year ago
  • nicol
    How to read plasticity chart?
    1 year ago
  • karen
    What is the significance of A line in plasticity chart?
    1 year ago
  • lemlem
    What classification does soil have on the plasticity chart?
    1 year ago
    How to draw plasticity chart in atterberg limit?
    1 year ago
  • Sirpa
    How to draw soil plastisity chart?
    1 year ago
  • Loredana
    What is the slope of Aline in the plasticity chart?
    12 months ago
  • Dorothy
    How is the plasticity chart useful in the classification for the fine grade?
    10 months ago
  • drew
    What is Plasticity charts?
    10 months ago
  • leroy
    Where from the equation of Aline comes from in soil mechanics?
    4 months ago
  • jeffery
    How to make a plasticity chart?
    3 months ago
  • semhar
    Which type of soil is ploted above Aline?
    2 months ago
  • elisa
    How to plot graph in soil machenics?
    2 months ago
  • johanna
    2 months ago
  • priscilla
    How to classify soil on plasticity chart if you can't roll out?
    11 days ago

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