View source: R/soilDeformation.R
soilDeformation | R Documentation |
It calculates bulk density variation as a function of the applied mean normal stress using critical state theory, by O'Sullivan and Robertson (1996).
soilDeformation(stress, p.density, iBD, N, CI, k, k2, m, graph = FALSE, ...)
stress |
a numeric vector containing the values of mean normal stress, kPa; Note that stress can also be a vector of length 1. |
p.density |
a numeric vector containing the values of particle density to each stress, Mg m^{-3}. |
iBD |
a numeric vector containing the values of initial bulk density to each stress, Mg m^{-3}. |
N |
the specific volume at p = 1 kPa, to each stress |
CI |
the compression index, to each stress; check details |
k |
the recompression index, to each stress; check details |
k2 |
the slope of the steeper recompression line to each stress (similar to the k' in O'Sullivan and Robertson (1996) model); check details |
m |
the value that separates yield line and VCL to each stress; check details |
graph |
logical; shall soilDeformation plot the graph model (only the first parameters set is ploted)? |
... |
further graphical arguments. See par. |
The specific volume (v) is given as v=PD/BD, where PD is particle density and BD is the bulk density. Please, check each parameter from O'Sullivan and Robertson (1996) model in the figure below.
A list of
iBD |
initial bulk density, Mg m^{-3} |
fBD |
final bulk density, Mg m^{-3} |
vi |
initial specific volume |
vf |
final specific volume |
I |
variation of soil bulk density (\%) after the applied stress |
Renato Paiva de Lima <renato_agro_@hotmail.com>
Anderson Rodrigo da Silva <anderson.agro@hotmail.com>
Alvaro Pires da Silva <apisilva@usp.br>
O'Sullivan, M.F.; Robertson, E.A.G. 1996. Critical state parameters from intact samples of two agricultural soils. Soil and Tillage Research, 39:161-173.
Keller, T.; Defossez, P.; Weisskopf, P.; Arvidsson, J.; Richard, G. 2007. SoilFlex: a model for prediction of soil stresses and soil compaction due to agricultural field traffic including a synthesis of analytical approaches. Soil and Tillage Research, 93:391-411.
# EXAMPLE 1 soilDeformation(stress = 300, p.density = 2.67, iBD = 1.55, N = 1.9392, CI = 0.06037, k = 0.00608, k2 = 0.01916, m = 1.3,graph=TRUE,ylim=c(1.4,1.8)) # EXEMPLE 2 (combining it with soil stress) stress <- stressTraffic(inflation.pressure=200, recommended.pressure=200, tyre.diameter=1.8, tyre.width=0.4, wheel.load=4000, conc.factor=c(4,5,5,5,5,5), layers=c(0.05,0.1,0.3,0.5,0.7,1), plot.contact.area = FALSE) stress.mean <- stress$Stress$sigma_mean layers <- stress$Stress$Layers n <- length(layers) def <- soilDeformation(stress = stress.mean, p.density = rep(2.67, n), iBD = rep(1.55,n), N = rep(1.9392,n), CI = rep(0.06037,n), k = rep(0.00608,n), k2 = rep(0.01916,n), m = rep(1.3,n),graph=TRUE,ylim=c(1.4,1.8)) # Graph plot(x = 1, y = 1, xlim=c(1.4,1.7),ylim=c(1,0),xaxt = "n", ylab = "Soil Depth",xlab ="", type="l", main="") axis(3) mtext("Bulk Density",side=3,line=2.5) initial.BD <- def$iBD final.BD <- def$fBD points(x=initial.BD, y=layers, type="l") points(x=initial.BD, y=layers,pch=15) points(x=final.BD, y=layers, type="l", col=2) points(x=final.BD, y=layers,pch=15, col=2) # End (not run)
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