Attachment C - Geotechnical investigation

PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007
APPENDIX C: — QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY (CONTINUED)

QUALITATIVE RISK ANALYSIS MATRIX- LEVEL OF RISK TO PROPERTY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LIKELIHOOD CON: SEQUEN CES TO PROPERTY (With Indicative Approximate Cost of Eomp.
Indicative Value of 1; CATASTROPHIC 2: MAJOR 3: MEDIUM 4: MINOR
Approximate Annual 200% 60% 20% 5% INSIGNIFIC ANT
Probability 0.5%
— ALMOST CERTAIN 107 H MorL (5)
- LIKELY 107 H M i
- POSSIBLE 107 M M VL
- UNLIKELY 10+ L L VL
- RARE 10° M £ “2 VL VL
- BARELY CREDIBLE 10* L VL VL VL VL

 

 

 

 

 

 

 

 

Notes: (5) For Cell A5, may be subdivided such that a consequence of less than 0.1% is Low Rusk.
(©) When considenng a nsk assessment it must be clearly stated whether it is for existing conditions or with nsk control measures which may not be implemented at the cwrent
time

RISK LEVEL IMPLICATIONS

 

Risk Level Example Implications (7)

Unacceptable without treatment. Extensive detailed investigation and research. planning and umplementation of treatment
options essential to reduce msk to Low; may be too expensive and not practical. Work likely to cost more than value of the
property.

Unacceptable without treatment. Detailed vestigation, planning and implementation of treatment options required to reduce

= Z ‘i nisk to Low. Work would cost a substantial sum m relation to the value of the property

 

May be tolerated m certain circumstances (subject to regulator's approval) but requires investigation, planning and
M MODERATE RISK unplementation of teatment options to reduce the nsk to Low. Treatment options to reduce to Low nsk should be
umplemented as soon as practicable

 

Usually acceptable to regulators. Where treatment has been required to reduce the nsk to this level, ongoing maimtenance is

L LOW RISK rompived

 

 

VL VERY LOW RISK Acceptable. Manage by normal slope maintenance procedures

 

 

 

Note: (7) The implications for a particular situation are to be determined by all partes to the msk assessment and may depend on the nature of the property at nsk: these are only
gtven as 2 general euide.

Australian Geomechanics Vol 42 No 1 March 2007
Form No. 68039 RL2 August 2010