Attachment 5 - Geotechnical Assessment · MCU18/0015

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RTI 11/055 Folio B428

 

 

METHOD OF SOIL DESCRIPTION
USED ON BOREHOLE AND TEST PIT REPORTS

 

GRAPHIC LOG - TYPICAL SYMBOLS FOR SOILS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FILL CLAY (CL, Cl OR CH)
Ko =o 2 ©4 ORGANIC SOILS
0 a
22 24 GRAVEL (GP OR GW) I. &« | OL OR OHOR Pt)
=< sou
Sw) SAND (SP OR SW) o(\¢| COBBLES OR BOULDERS
& * « “I SILT (ML OR MH)

 

 

Combinations of these basic symbols may be used to indicate mixed materials such as sandy clay.

 

CLASSIFICATION AND INFERRED STRATIGRAPHY

Soil and Rock ts classified and described in Reports of Boreholes and Test Pits using the preferred method given in
AS1726 - 1993, Appendix A. The material properties are assessed in the field by visual/tactile methods.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Particle Size Plasticity Properties
Major Division |Sub Division |Particle Size 40
BOULDERS > 200 mm cH
cl High plasticity
COBBLES 63 to 200 mm Medium clay
= vm
Coarse 20 to 63 mm g Low peau ¥
GRAVEL Medium 6.0 to 20 mm 5 ony
Fine 2.0 to 6.0 mm . 20 High taut limit
hod sit
Coarse 0.6 to 2.0 mm 3
SAND Medium 0.2 to 0.6 mm a 10 Medium gula
Fine 0.075 to 0.2 mm CLIFIL Ctay/Sit limit sit
ML - Low liquid limit silt
SILT 0.002 to 0.075 rim 0
0 40 20 30 40 50 60 70 80
CLAY < 0.99 2m Liquid Limit (%)
MOISTURE CONDITION . AS1726 - 1993
Symbol Term Description
D Dry Sands and gravels are free flowing. Clays & Silts may be brittle or friable and powdery.
M Moist Soils are darker than in the dry condition & may feel cool. Sands and gravels tend to cohere.
W Wet Soils exude free water. Sands and gravels tend to cohere.
CONSISTENCY AND DENSITY AS1726 - 1993
Symbol Term Undrained Shear Symbol Term Density Index % SPT "N” #
Strength
VS Very Soft 0 to 12 kPa VL Very Loose Less than 15 0to4
Soft 12 to 25 kPa L Loose 15 to 35 4to 10
Firm 25 to 50 kPa MD | Medium Dense 35 to 65 10 to 30
St Stiff 50 to 100 kPa D Dense 65 to 85 30 to 50
vst Very Stiff 100 to 200 kPa VD Very Dense above 85 Above 50
H Hard above 200 kPa

 

 

 

 

 

 

 

 

 

 

# SPT correlations are not stated in AS1726 — 1993, and may be subject to corrections for overburden pressure and
equipment type.

In the absence of test results, consistency and density may be assessed from correlations with the observed behaviour of
the material.

 

 

GAP Fonn No, 5
RLA