Reference Documents

                                                                                           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
                  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 - 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.




                                                                                                                                                     Rev1
                                                                                                                                             October 2017
Document Set ID: 22826802
Version: 1, Version Date: 23/02/2024