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RFI -Attachment 6 - Geotechnical Investigation Report CORE
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TERMS FOR ROCK MATERIAL STRENGTH & WEATHERING AND
ABBREVIATIONS FOR DEFECT DESCRIPTIONS
ROCK MATERIAL STRENGTH CLASSIFICATION AS1726—2017
Symbol Term Uniaxial Point Load Field Guide
Strength Is (50)
Compressive
(MPa)
Strength (MPa)
VL Very Low 0.6 to 2 0.03 to 0.1 Material crumbles under firm blows with sharp end of pick. Pieces up to 30 mm thick can
Strength be broken with finger pressure.
L Low Strength 2 to 6 0.1 to 0.3 Easily scored with knife. Indentations 1 mm to 3 mm show in the specimen with firm
blows of the pick point. A piece of core 150 mm by 50 mm may be broken by hand. Sharp
edges of core are friable and break during handling.
M Medium 6 to 20 0.3 to 1 Readily scored with a knife. A piece of core 150 mm by 50 mm can be broken by hand
Strength with difficulty.
H High Strength 20 to 60 1 to 3 A piece of core 150 mm by 50 mm cannot be broken by hand but can be broken by a pick
with a single firm blow. Rock rings under hammer.
VH Very High 60 to 200 3 to 10 Hand specimen breaks with pick after more than one blow. Rock rings under hammer.
Strength
EH Extremely High Above 200 Above 10 Specimen requires many blows with geological pick to break through intact material. Rock
Strength rings under hammer.
= Diametral Point Load Test = Axial Point Load Test
CLASSIFICATION OF MATERIAL AS1726—2017
WEATHERING
Symbol Term Field Guide
RS Residual Soil (Note 1) Material is weathered to such an extent that it has soil properties. Mass structure and material texture and
fabric of original rock are no longer visible but the soil has not been significantly transported.
XW Extremely Weathered Material is weathered to such an extent that is has soil properties. Mass structure and material texture and
(Note 1) fabric of original rock are still visible.
HW Highly Weathered (Note 2) The whole rock mass is discoloured, usually by iron staining or beaching to the extent that the colour of the
original rock is not recognizable. Rock strength is significantly changed by weathering. Some primary miner-
als have weathered to clay minerals. Porosity may be increased by leaching, or may be decreased due to
deposition of weathering products in pores.
MH Moderately Weathered The whole of the rock material is discoloured, usually by iron staining or bleaching to the extent that the
(Note 2) colour of the original rock is not recognizable, but shows little or no change in strength from fresh rock.
SW Slightly Weathered Pock is partially discoloured with staining or bleaching along joints but shows little or no change of strength
from fresh rock.
FR Fresh Rock shows no signs of decomposition of individual minerals or colour change.
Note 1 The term ‘Extremely Weathered rock’ is misleading as the material has soil properties. The word ‘rock’ should be replaced with the name
of the original rock of the word ‘material’, eg. Extremely Weathered granite or Extremely Weathered material.
Note 2 Where it is not possible to distinguish between ‘Highly Weathered’ and ‘Moderately Weathered’ rock the term ‘Distinctly Weathered’ may
be used.
DEFECT TYPE/DESCRIPTION DEFECT PROFILE DEFECT ROUGHNESS
Symbol Description DESCRIPTION
B Bedding Parting V Vein
PL Planar
Symbol Description
J Joint HB/DB Handling/Drilling St Stepped
Break Sl Slickenside
Un Undulating
EW Extremely Weathered C Contact Sm Smooth
DEFECT INFILL DESCRIPTION
Seam
Symbol Description Ro Rough
FZ Fracture Zone L Cleavage Vertical Boreholes - The dip
Cn Clean: No visible
coating (inclination from horizontal) for the
CZ/S Crushed Zone/Seam X Foliation defect is given.
Sn Stain: Coated 1 to
3 mm Inclined Boreholes - The inclination
IS Infilled Seam S Schistocity is measured as the acute angle to the
Vr Veneer: < 1 mm core axis.
SZ/S Sheared Zone/Seam Ct Coating: 1 to 3
mm
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