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r.rock.stability

A tool for preliminary rock failure susceptibility mapping.

r.rock.stability dem=string imme=integer incl=integer f4=string rmr=string prefix=string [tc=float] [imme2=integer] [incl2=integer] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]

Example:

r.rock.stability dem=string imme=integer incl=integer f4=string rmr=string prefix=string

grass.script.run_command("r.rock.stability", dem, imme, incl, f4, rmr, prefix, tc=None, imme2=None, incl2=None, overwrite=False, verbose=False, quiet=False, superquiet=False)

Example:

gs.run_command("r.rock.stability", dem="string", imme=integer, incl=integer, f4="string", rmr="string", prefix="string")

Parameters

dem=string [required]
    Dtm of the zone
imme=integer [required]
    Dip direction of the joint (0-360)
    Allowed values: 0-360
incl=integer [required]
    Dip of the joint (0-90)
    Allowed values: 0-90
f4=string [required]
    F4 index
    Allowed values: Natural Slope +15, Pre-splitting +10, Smooth blasting +8, Normal blasting or mechanical excavation 0, Poor blasting -8
rmr=string [required]
    RMR index
prefix=string [required]
    Prefix for output maps
tc=float
    Total Condition of joint, for SSPC output
    Allowed values: 0.018975 - 1.0165
imme2=integer
    Dip direction of the joint (0-360). For SMR_wedge output
    Allowed values: 0-360
incl2=integer
    Dip of the joint (0-90). For SMR_wedge output
    Allowed values: 0-90
--overwrite
    Allow output files to overwrite existing files
--help
    Print usage summary
--verbose
    Verbose module output
--quiet
    Quiet module output
--qq
    Very quiet module output
--ui
    Force launching GUI dialog

dem : str, required
    Dtm of the zone
    Used as: input, raster
imme : int, required
    Dip direction of the joint (0-360)
    Allowed values: 0-360
incl : int, required
    Dip of the joint (0-90)
    Allowed values: 0-90
f4 : str, required
    F4 index
    Allowed values: Natural Slope +15, Pre-splitting +10, Smooth blasting +8, Normal blasting or mechanical excavation 0, Poor blasting -8
rmr : str, required
    RMR index
    Used as: input, raster
prefix : str, required
    Prefix for output maps
tc : float, optional
    Total Condition of joint, for SSPC output
    Allowed values: 0.018975 - 1.0165
imme2 : int, optional
    Dip direction of the joint (0-360). For SMR_wedge output
    Allowed values: 0-360
incl2 : int, optional
    Dip of the joint (0-90). For SMR_wedge output
    Allowed values: 0-90
overwrite: bool, optional
    Allow output files to overwrite existing files
    Default: False
verbose: bool, optional
    Verbose module output
    Default: False
quiet: bool, optional
    Quiet module output
    Default: False
superquiet: bool, optional
    Very quiet module output
    Default: False

DESCRIPTION

Two important steps can be recognised in the rockfall analysis: the potential failure detection and the run out simulation. Analyzing the stability of rock slopes, most important kinematisms are slidings (planar or wedge) and topplings. r.rock.stability is a module that allows users to apply geomechanical classifications (SMR and SSPC) for the preliminary assessment of the susceptibility of rock slopes to failures induced by these kinematisms.

SMR approach (default):SMR (Slope Mass Rating) is a widely used geomechanical classification developed by Romana (1995). The final SMR rating is obtained by means of next expression: SMR=RMRb+(F1*F2*F3)+F4 where:

  • RMRb is the RMR index resulting from Bieniawski's Rock Mass Classification (1989)
  • F1 depends on the parallelism between discontinuity and slope dip direction
  • F2 depends on the discontinuity dip in the case of planar failure and the plunge, or of the intersection line in wedge failure. As regards toppling failure, this parameter takes the value 1.0
  • F3 depends on the relationship between slope and discontinuity dips (toppling or planar failure cases) or the immersion line dip (wedge failure case)
  • F4 is a correction factor that depends on the excavation method used:
  • Natural Slope +15
  • Pre-splitting +10
  • Smooth blasting +8
  • Normal blasting or mechanical excavation 0
  • Poor blasting -8

r.rock.stability calculate F1, F2 and F3 index by combining DEM (slope and aspect) and joint dip and dip direction.

F1, F2 and F3 are calculated according two functions of Romana (1995) and of Tomàs et al. (2007). The functions proposed by Romana are discrete, instead Tomàs et al. (2007) proposed continuous functions that reduced subjective interpretations.

SSPC approach (optional): inserting TC value (or a map of TC values) it's possible to obtain a SSPC map according to Hack's classification (Hack, 1998). Only a part of the method introduced by Hack is used in the module: the orientation dependent stability (the stability depend on relation between slope and discontinuity orientation). According to the author:

  • sliding occurs if: TC \< 0,0113*AP
  • toppling occurs if: TC \< 0,0087*(-90-AP+dip)

where AP is the apparent dip, TC is the condition factor for a discontinuity. TC can be calculated by multiplying the large scale roughness, the small scale roughness, the infill material and the karst factors observed in the field:

TC=Rl Rs Im Ka.

Rl (roughness in large scale - area between 0,2x0,2 m2 and 1x1 m2)

  • 1,00 Wavy
  • 0,95 Slightly wavy
  • 0,85 Curved
  • 0,80 Slightly curved
  • 0,75 Straight

Rs (roughness in small scale - area of 0,2x0,2m2):

  • 0,95 Rough stepped
  • 0,90 Smooth stepped
  • 0,85 Polished stepped
  • 0,80 Rough undulating
  • 0,75 Smooth undulating
  • 0,70 Polished undulating
  • 0,65 Rough planar
  • 0,60 Smooth planar
  • 0,55 Polished planar.

Im (Infill material)

  • Cemented --> Infill (1,07), No Infill (1,00)
  • Non softening and sheared material e.g. free of clay, talc, etc --> Coarse (0,95) Medium (0,90) Fine (0,85)
  • Soft sheared material e.g. clay, talc, etc --> Coarse (0,75) Medium (0,65) Fine (0,55)
  • Gouge \< irregularities (0,42); Gouge > irregularities (0,17); flowing material (0,05)

Ka (karst):

  • 1,00 None
  • 0.92 Karst

NOTE: high pixel values indicate high susceptibility

SMR wedge (optional): inserting dip and dip direction it's possible to calculate the SMR index of wedge.

INPUT

Digital Elevation Model: Name of elevation raster map

Dip direction: Value of the direction of the discontinuity measured clockwise starting from North. North is 0 or 360 degrees, East (90 degrees), South (180 degrees), West (270 degrees)

Dip: Angle of inclination of the discontinuity relative to a horizontal plane.

F4: Correction factor according to Romana's classification

RMR: Value of RMRb according to Bieniawski's classification

TC (optional): Value of TC according to Hack's classification

Output prefix: Name of prefix used for output raster maps

OUTPUT

r.rock.stability generates 3 raster maps of SMR (prefix_toppling; prefix_planar; prefix_wedge;) values distribution according to mechanism: planar sliding, toppling and wedge (if optional dip and dip direction is inserted).

SMR classes SMR values Suggest supports
Ia 91-100 None
Ib 81-90 None, scaling is required
IIa 71-80 (None, toe ditch or fence), spot bolting
IIb 61-70 (Toe ditch or fence nets), spot or systematic bolting
IIIa 51-60 (Toe ditch and/or fence nets), spot or systematic bolting, spot shotcrete
IIIb 41-50 (Toe ditch and/or fence nets), spot or systematic bolting/anchor, toe wall and/or dental concrete
IVa 31-40 Anchor systematic shotcrete, toe wall and/or dental concrete (or re-excavation), drainage
IVb 21-30 Systematic reinforced shotcrete, toe wall and/or concrete, re-excavation, deep drainage
Va 11-20 Gravity or anchored wall, re-excavation

REFERENCES

BIENIAWSKI Z.T. (1989). Engineering Rock Mass Classifications. John Wiley and Sons: New York.

FILIPELLO A., GIULIANI A., MANDRONE G. (2010) - Rock Slopes Failure Susceptibility Analysis: From Remote Sensing Measurements to Geographic Information System Raster Modules. American Journal of Environmental Sciences 6 (6): 489-494, 2010 ISSN 1553-345X © 2010 Science Publications.

HACK HRGK (1998) Slope stability probability classification, SSPC, 2nd edn. ITC, Enschede, The Netherlands, 258 pp, ISBN 90 6164 154 3

ROMANA M. (1995). The geomechanical classification SMR for slope correction. Proc. Int. Congress on Rock Mechanics 3: 1085-1092.

TOMÀS, R., DELGADO, J.,SERON, J.B. (2007). Modification of slope mass rating(SMR) by continuous functions. International Journal of Rock Mechanics and Mining Sciences 44: 1062-1069.

SEE ALSO

AUTHORS

Andrea Filipello, University of Turin, Italy

Daniele Strigaro, University of Milan, Italy

SOURCE CODE

Available at: r.rock.stability source code (history)
Latest change: Thursday Mar 20 21:35:59 2025 in commit f270357