# simSigmaP: Simulating Preconsolidation Stress In soilphysics: Soil Physical Analysis

## Description

Simulating preconsolidation pressure, compression and swelling indices, based on a multivariate Gaussian distribution for the parameters of the compression curve.

## Usage

 ```1 2 3 4``` ```simSigmaP(voidratio, stress, what.out = c("sigmaP", "CI", "SI"), method = c("casagrande", "VCLzero", "reg1", "reg2", "reg3", "reg4", "pacheco"), n4VCL = 3, nsim = 100) ```

## Arguments

 `voidratio` a numeric vector containing void ratio (or bulk density) values. `stress` a numeric vector containing the applied stress sequence. `what.out` a character indicating which `sigmaP()` output should be simulated. It must be on of "sigmaP" (default), "CI" of "SI". `method` a character vector indicating which methods should be used. `n4VCL` the number of points for calculating the slope of the soil Virgin Compression Line (VCL), which is obtained by linear regression. Default is 3. `nsim` the number of simulations. Default is 100. Warning: it may cause time demanding.

## Value

A numeric matrix containing the simulated values for each method selected as input.

## Author(s)

Anderson Rodrigo da Silva <anderson.agro@hotmail.com>

`sigmaP`, `plotCIsigmaP`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14``` ```# input data: stress and void ratio pres <- c(1, 12.5, 25, 50, 100, 200, 400, 800, 1600) VR <- c(1.43, 1.41, 1.40, 1.39, 1.35, 1.31, 1.25, 1.18, 1.12) # simulation (may take a few seconds) simres <- simSigmaP(VR, pres, nsim = 30) head(simres) # plot percentile confidence intervals ci <- plotCIsigmaP(simres, conf.level = 0.95, shade.col = "blue", ordered = TRUE) print(ci) # End (Not run) ```