Grain Size Analysis

Grain Size Analysis

Introduction

Rocks or soils are examples of granular materials that are frequently categorized using their particle size scattering. Grain spread is also useful as an indication of the rock characteristics, such as shear strength, permeability, compressibility, and porosity. Grain size heavily relies on the method of measurement, dimension, and length. Typically, there are two main methods for determining particle spread and sizes, which are the hydrometer method for analysis of grains with smaller particles and sieve analysis for the study of particles averagely larger than 0.075mm.

Theory

The sieve analysis method involves shaking the granular material under test on a sieve with square openings of a given size. Thus, the size of the particles shall be grounded on the dimensions of the square hole in a screen. A medium that is porous and composed exclusively of the particles of a given size is said to be uniform. On the other hand, grains of different sizes are to be graded and well-graded if the grains are distributed regularly. Effective grain size  is a grain of diameter greater than that of 10% of the particles by weight and denoted by

Data Analysis

Calculations

Plots

• Uniformity coefficient
• Effective size
• Proper screen pipe size

This is mesh number 60

• The geometric mean
• The standard deviation
• The approximated permeability 

   

   

   

  Grain Size Analysis

  Introduction

  Rocks or soils are examples of granular materials that are frequently categorized using their particle size scattering. Grain spread is also useful as an indication of the rock characteristics, such as shear strength, permeability, compressibility, and porosity. Grain size heavily relies on the method of measurement, dimension, and length. Typically, there are two main methods for determining particle spread and sizes, which are the hydrometer method for analysis of grains with smaller particles and sieve analysis for the study of particles averagely larger than 0.075mm.

  Theory

  The sieve analysis method involves shaking the granular material under test on a sieve with square openings of a given size. Thus, the size of the particles shall be grounded on the dimensions of the square hole in a screen. A medium that is porous and composed exclusively of the particles of a given size is said to be uniform. On the other hand, grains of different sizes are to be graded and well-graded if the grains are distributed regularly. Effective grain size  is a grain of diameter greater than that of 10% of the particles by weight and denoted by

   

  Data Analysis

  Calculations

  Mesh No	Screen Opening			Weight of the empty sieve	Weight of the empty sieve and sand	Weight of sand retained	Percent by weight retained	Total Losses	Losses distribution	Total weight retained	Total percent by weight retained	Cumulative total percent by weight retained
  	Microns	mm	In Units	(g)	(g)	Wi (g)	Fraction	(g)	(g)	(g)	(%)	(%)
  Retained  on 20	850	0.85	0.234465	338.44	338.44	0	0	299.9	0	0	0	0
  Retained  on 30	600	0.6	0.736966	332.37	332.47	0.1	0.033344	298.9	0.149524762	0.249525	0.055985115	0.055985115
  Retained  on 40	425	0.425	1.234465	310.43	310.78	0.35	0.116706	299.45	0.52429965	0.8743	0.196163964	0.252149079
  Retained  on 60	250	0.25	2	282.4	371.89	89.49	29.83995	209.96	93.9935988	183.4836	41.1676593	41.41980838
  Retained  on 80	180	0.18	2.473931	287.72	434.07	146.35	48.7996	63.61	46.56990245	192.9199	43.28485416	84.70466254
  Retained  on 100	150	0.15	2.736966	272.69	311.55	38.86	12.95765	24.75	4.811330665	43.67133	9.798404182	94.50306672
  Retained  on 140	106	0.106	3.237864	276.54	297.49	20.95	6.985662	3.8	0.398249125	21.34825	4.789841993	99.29290871
  Retained  on 170	90	0.09	3.473931	275.81	277.88	2.07	0.69023	1.73	0.017914457	2.087914	0.468459043	99.76136776
  Retained  on 200	75	0.075	3.736966	273.23	274.29	1.06	0.353451	0.67	0.003552776	1.063553	0.238626115	99.99999387
  Passed 200	53	0.05	4.321928	269.68	270.35	0.67	0.223408	0	0		n/a	n/a
  Retained  in pan	0	0		266.54	0	0	0	0
  Total						299.9				445.6984

  Plots

  • Uniformity coefficient
  • Effective size
  • Proper screen pipe size

  This is mesh number 60

  • The geometric mean
  • The standard deviation
  • The approximated permeability