Compute uniformity and curvature coefficients from a grain-size distribution

Calculates the uniformity coefficient and the curvature coefficient from percent passing data. The characteristic diameters can be supplied directly or derived from sieve numbers or particle sizes.

Usage

grainSize.coefs(
  percent,
  sieve = NA,
  size = NA,
  D10 = NA,
  D30 = NA,
  D60 = NA,
  metric = T
)

Arguments

percent

Numeric vector of percent passing values (0–100).

sieve

Numeric vector of ASTM sieve numbers. Used when size is not provided. Default NA.

size

Numeric vector of particle sizes (mm if metric = TRUE, inches otherwise). Default NA.

D10

Diameter at 10 percent passing. If NA (default) it is interpolated from the data.

D30

Diameter at 30 percent passing. If NA (default) it is interpolated from the data.

D60

Diameter at 60 percent passing. If NA (default) it is interpolated from the data.

metric

Logical. If TRUE (default) sizes are in millimetres.

Value

A named list with components Cu (uniformity coefficient) and Cc

Details

This function is taken from the "geotech" package from James Kaklamanos (curvature coefficient).

See also

Other soil mechanics, classification: Dsize(), USCS(), USCS.coarse.symbol(), USCS.fine.symbol(), percentComponents(), size.from.sieve()

Examples

grainSize.coefs(
  percent = c(0, 10, 30, 60, 90, 100),
  size    = c(0.075, 0.15, 0.3, 0.6, 1.18, 2.36)
)
#> $Cu
#> [1] 4
#> 
#> $Cc
#> [1] 1
#>