soilphysics (version 5.0)

fitlbc: Parameter Estimation of the Load Bearing Capacity Model

Description

This function creates initial parameter estimates of the nonlinear Load Bearing Capacity (Dias Jr., 1994) model, i.e., \(\sigma_P = 10 ^ {(b0 + b1 * \theta)}\), by using two methods: a getInitial method or a log-linearization. Then, it uses them to provide its least-squares estimates via nls.

Usage

fitlbc(theta, sigmaP, ...)

Arguments

theta

a numeric vector containing soil moisture values.

sigmaP

a numeric vector containing values of soil preconsolidation stress.

…

further arguments to nls.

Value

A nls object.

References

Dias Junior, M. S. (1994). Compression of three soils under longterm tillage and wheel traffic. 1994. 114p. Ph.D. Thesis - Michigan State University, East Lansing.

See Also

sigmaP, fitbusscher, maxcurv, Rsq

Examples

# NOT RUN {
data(compaction)
attach(compaction)
out <- fitlbc(theta = Mois, sigmaP = PS)
summary(out)
Rsq(out)
curve(10^(coef(out)[1] + coef(out)[2]*x))

# End (not run)
# }