OPW052025 Report - Part 2

                                                                         METHOD OF SOIL DESCRIPTION
                                                                                      USED ON LOGS
CLASSIFICATION AND INFERRED STRATIGRAPHY
Soil is classified and described in borehole and test pit logs using the preferred method given in AS1726 – 2017.
The material properties are assessed in the field by visual/tactile methods.
Particle Size                                                                      Plasticity Properties

 Major          Sub Division           Particle Size
Division
          BOULDERS                     > 200 mm
           COBBLES                    63 to 200 mm
                  Coarse               19 to 63 mm
 GRAVEL           Medium               6.7 to 19 mm
                       Fine           2.36 to 6.7 mm
                  Coarse              0.6 to 2.36 mm
  SAND            Medium              0.21 to 0.6 mm
                   Fine               0.075 to 0.21
                SILT                  0.002 to 0.075
             CLAY                      < 0.002 mm
                                                          NOTE: The U line is an approximate upper bound for most materials.
                                                          Data which plot above the U line may represent unusual/problem soil
                                                          behavior, or unreliable data and should be considered carefully.

MOISTURE CONDITION                                               AS1726 - 2017

Coarse Grained Soils
Symbol       Term             Description
   D             Dry          Sands and gravels are free flowing.
   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
Fine Grained Soils
Symbol        Description
  w < PL      Moist, dry of plastic limit, (hard and friable or powdery)
  w = PL      Moist, near plastic limit, (soils can be moulded at a moisture content approximately equal to the plastic limit)
  w > PL      Moist, wet of plastic limit, (soils usually weakened and free water forms on hands when handling)
  w = LL      Wet, near liquid limit
  w > LL      Wet, wet of liquid limit

CONSISTENCY AND DENSITY                                         AS1726 - 2017
 Symbol      Term       Undrained Shear                       Symbol        Term              Density Index %        SPT “N” #
                           Strength
    VS           Very Soft             0 to 12 kPa               VL         Very Loose          Less than 15            0 to 4
    S              Soft               12 to 25 kPa                  L          Loose               15 to 35            4 to 10
    F              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
In the absence of test results, consistency and density may be assessed from correlations with the observed behaviour of
the material.
# SPT correlations are not stated in AS1726 – 2017, and may be subject to corrections for overburden pressure and
equipment type.




                                                                                                                               Rev3
                                                                                                                      November 2024