Grain-Size Distribution Functions

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Description

These functions compute diferent aspects related to grain-size distributions of soil.

Usage

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size.from.sieve(sieve, metric)
grainSize.plot(sieve = NA, size = NA, percent, metric)
percentComponents(sieve = NA, size = NA, percent, metric)
Dsize(N, sieve = NA, size = NA, percent, metric)
grainSize.coefs(percent, sieve = NA, size = NA, D10 = NA,
                D30 = NA, D60 = NA)

Arguments

sieve

vector of sieve numbers according to ASTM D422

size

vector of grain sizes (in or mm)

percent

vector of percent passing

metric

logical variable: TRUE for metric units (mm), FALSE for English units (in)

N

the percent corresponding to the desired D-size

D10

D-size corresponding to 10 percent passing

D30

D-size corresponding to 30 percent passing

D60

D-size corresponding to 60 percent passing

Details

  • Either sieve numbers (sieve) OR grain sizes (size) must be provided in all functions; however, in grainSize.coefs the user additionally has the option of specifying D10, D30, and D60.

  • For sieves larger than the no. 4 sieve, the user should specify the sieve size in inches (e.g., 3/8, 3/4, 1, 1.5, 2, 3, etc.).

  • The argument percent is required in all functions except size.from.sieve, and the argument metric is required in all functions except for grainSize.coefs and Dsize (although it is needed in Dsize if sieve numbers are provided).

  • The percentComponents function assumes that the no. 4 and no. 200 sieves have been used.

Value

  • sieve.from.size calculates a set of grain sizes corresponding to a set of sieves (output is vector of grain sizes (in or mm)

  • grainSize.plot creates a plot of the soil's grain-size distribution; no numerical values are output

  • percentComponents is used to calculate the percent gravel, sand, and fines, and outputs a three-element list:

    1. pg = Percent gravel

    2. ps = percent sand

    3. pf = percent fines

  • Dsize outputs the grain size corresponding to a certain percent finer (N), given a grain-size distribution

  • grainSize.coefs calculates the coefficients of uniformity and curvature, and outputs a two-element list:

    1. Cu = Coefficient of uniformity (D60 / D10)

    2. Cc = Coefficient of Curavture (D30^2 / (D10 * D60))

Note

The Dsize function uses logarithmic interpolation to calculate the D-size from the provided grain-size distribution. Log-linear extrapolation is used for grain sizes beyond the range of the data, and a warning is provided.

Author(s)

James Kaklamanos <kaklamanosj@merrimack.edu> and Kyle Elmy <ElmyK@merrimack.edu>

See Also

USCS, AASHTO, Plasticity

Examples

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##  Example 1:  Grain-size distribution

##  (a) Define data
sieve.example <- c(3/8, 4, 10, 20, 40, 140, 200)
percent.example <- c(95.72, 90.23, 81.49, 66.36, 50.00, 8.51, 4.82)

##  (b) Percent gravel, sand, and fines
percentComponents(sieve = sieve.example, percent = percent.example,
                  metric = TRUE)

##  (c) Plot grain-size distribution
grainSize.plot(sieve = sieve.example, percent = percent.example,
               metric = TRUE)

##  (d) Calculate D50
Dsize(N = 50, sieve = sieve.example, percent = percent.example,
      metric = TRUE)

##  (e) Coefficients of uniformity and curvature
grainSize.coefs(sieve = sieve.example, percent = percent.example)


##  Example 2:  coefficients of uniformity and curvature
grainSize.coefs(D60 = 0.10, D30 = 0.03, D10 = 0.002)