Description Usage Arguments Details Value Author(s) References Examples

View source: R/soilDeformation.R

It calculates bulk density variation as a function of the applied mean normal stress using critical state theory, by O'Sullivan and Robertson (1996).

1 | ```
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, |

`iBD ` |
a numeric vector containing the values of initial bulk density to each stress, |

`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, |

`fBD ` |
final bulk density, |

`vi` |
initial specific volume |

`vf ` |
final specific volume |

`I` |
variation of soil bulk density ( |

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.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | ```
# 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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