Reference Document - MCU24/0143 (As Published)

                                                                                            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
Document Set ID: 24125427
                  24010296
Version: 1, Version Date: 17/09/2025
                          07/08/2025