SAFETYFACTOR
- Author: A. Günther (c) 2012
- Menu: Terrain Analysis | Slope Stability
Description
This tool computes a slope stability (expressed as a factor-of-safety) raster according to the traditional infinite slope model theory (see cf Selby, 1993) The resulting raster represents the ratio of resisting forces/driving forces (fs) on a potential shear plane with fs lesser 1 unstable, fs greater 1 stable. Except for a slope raster (in radians), all input variables can be specified either globally or distributed (through grids). The tool creates a continuous fs raster (values above 10 are truncated), and a binary stability grid with nodata = stable, 1 = unstable (optional).
Parameters
| Name | Type | Identifier | Description | Constraints | |
|---|---|---|---|---|---|
| Input | Slope grid (rad) | grid, input | A | A slope angle grid (in rad__ans) | - |
| Min thickness grid (m) | grid, input, optional | Bmin | A grid representing minimum cell layer thicknesses to potential shear plane (in meters) | - | |
| Max thickness grid (m) | grid, input, optional | Bmax | A grid representing maximum cell layer thicknesses to potential shear plane (in meters) | - | |
| Min saturation grid (-) | grid, input, optional | Cmin | A grid representing minimum cell relative water saturation of layer (dimensionless) | - | |
| Max saturation grid (-) | grid, input, optional | Cmax | A grid representing maximum cell relative water saturation of layer (dimensionless) | - | |
| Min friction grid (degree) | grid, input, optional | Dmin | A grid representing minimum cell frictional shear strength of layer (in degrees) | - | |
| Max friction grid (degree) | grid, input, optional | Dmax | A grid representing maximum cell frictional shear strength of layer (in degrees) | - | |
| Min density grid (g/cm3) | grid, input, optional | Emin | A grid representing minimum cell bulk density of layer (in grams per cubiccentimeters) | - | |
| Max density grid (g/cm3) | grid, input, optional | Emax | A grid representing maximum cell bulk density of layer (in grams per cubiccentimeters) | - | |
| Min cohesion grid (MPa) | grid, input, optional | Fmin | A grid representing minimum cell layer cohesion (in Megapascals) | - | |
| Max cohesion grid (MPa) | grid, input, optional | Fmax | A grid representing maximum cell layer cohesion (in Megapascals) | - | |
| Output | FS values | grid, output | G | Resulting factor-of-safety (-) grid | - |
| FS classes | grid, output, optional | H | Resulting stability (0/1) grid | - | |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Min global thickness (m) | floating point number | fBmin | Constant value if no raster set | Default: 1.000000 | |
| Max global thickness (m) | floating point number | fBmax | Constant value if no raster set | Default: 1.000000 | |
| Min global saturation (-) | floating point number | fCmin | Constant value if no raster set | Default: 0.000000 | |
| Max global saturation (-) | floating point number | fCmax | Constant value if no raster set | Default: 0.000000 | |
| Min global friction (degree) | floating point number | fDmin | Constant value if no raster set | Default: 33.000000 | |
| Max global friction (degree) | floating point number | fDmax | Constant value if no raster set | Default: 33.000000 | |
| Min global density (g/cm3) | floating point number | fEmin | Constant value if no raster set | Default: 1.600000 | |
| Max global density (g/cm3) | floating point number | fEmax | Constant value if no raster set | Default: 1.600000 | |
| Min global cohesion (MPa) | floating point number | fFmin | Constant value if no raster set | Default: 0.000000 | |
| Max global cohesion (MPa) | floating point number | fFmax | Constant value if no raster set | Default: 0.000000 | |
| Parameter sampling runs | integer number | fI | Number of sampling cycles | Default: 1 |
Command Line
Usage: saga_cmd ta_slope_stability 0 [-A] [-Bmin ] [-Bmax ] [-Cmin ] [-Cmax ] [-Dmin ] [-Dmax ] [-Emin ] [-Emax ] [-Fmin ] [-Fmax ] [-fBmin ] [-fBmax ] [-fCmin ] [-fCmax ] [-fDmin ] [-fDmax ] [-fEmin ] [-fEmax ] [-fFmin ] [-fFmax ] [-fI ] [-G ] [-H ] -A: Slope grid (rad) grid, input -Bmin: Min thickness grid (m) grid, input, optional -Bmax: Max thickness grid (m) grid, input, optional -Cmin: Min saturation grid (-) grid, input, optional -Cmax: Max saturation grid (-) grid, input, optional -Dmin: Min friction grid (degree) grid, input, optional -Dmax: Max friction grid (degree) grid, input, optional -Emin: Min density grid (g/cm3) grid, input, optional -Emax: Max density grid (g/cm3) grid, input, optional -Fmin: Min cohesion grid (MPa) grid, input, optional -Fmax: Max cohesion grid (MPa) grid, input, optional -fBmin: Min global thickness (m) floating point number Default: 1.000000 -fBmax: Max global thickness (m) floating point number Default: 1.000000 -fCmin: Min global saturation (-) floating point number Default: 0.000000 -fCmax: Max global saturation (-) floating point number Default: 0.000000 -fDmin: Min global friction (degree) floating point number Default: 33.000000 -fDmax: Max global friction (degree) floating point number Default: 33.000000 -fEmin: Min global density (g/cm3) floating point number Default: 1.600000 -fEmax: Max global density (g/cm3) floating point number Default: 1.600000 -fFmin: Min global cohesion (MPa) floating point number Default: 0.000000 -fFmax: Max global cohesion (MPa) floating point number Default: 0.000000 -fI: Parameter sampling runs integer number Default: 1 -G: FS values grid, output -H: FS classes grid, output, optional