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Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.


r.rock.stability - A tool for preliminary rock failure susceptibility mapping.


rock mass, planar failure, toppling


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


Allow output files to overwrite existing files
Print usage summary
Verbose module output
Quiet module output
Force launching GUI dialog


dem=string [required]
Dtm of the zone
imme=integer [required]
Dip direction of the joint (0-360)
Options: 0-360
incl=integer [required]
Dip of the joint (0-90)
Options: 0-90
f4=string [required]
F4 index
Options: 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
Total Condition of joint, for SSPC output
Options: 0.018975 - 1.0165
Dip direction of the joint (0-360). For SMR_wedge output
Options: 0-360
Dip of the joint (0-90). For SMR_wedge output
Options: 0-90

Table of contents


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:

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:

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)

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

Im (Infill material)

Ka (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.


Digital Elevation Model = name

Dip direction = string

Dip = string

F4 = string

RMR = string or map

TC (optional) = string or map

Output prefix = name


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


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.



Andrea Filipello, University of Turin, Italy

Daniele Strigaro, University of Milan, Italy


Available at: r.rock.stability source code (history)

Latest change: Monday Jan 30 19:52:26 2023 in commit: cac8d9d848299297977d1315b7e90cc3f7698730

Note: This document is for an older version of GRASS GIS that will be discontinued soon. You should upgrade, and read the current manual page.

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