Response to Information Request - Received on 19/04/2012 · OPW11/0335

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     Notes on Description and Classification of Soil


     The methods of description and classification of soils used in this report are generally based on Australian Standard AS1726-1993 ’Geotechnical Site
     Investigations’.

     Soil description is based on an assessment of disturbed samples, as recovered from bores and excavations, or from undisturbed malerials as seen in
     excavations and exposures or in undisturbed samples. Descriptions given on report sheets are an interpretation of the conditions encountered at the time
     of invest aUon.


     In the case of cone or piezocone penetrometer tests, actual soil samples are not recovered and soil description is inferred based on published correlations,
     past experience and comparison with bore andlor test pit data (if available).

     Soil classification is based on the particle size distribution of the soil and the plasticity of the portion of the material finer than 0.42Smm. The description of
     particle size distribution and plasticity is based on the results of visual field estimation, laboratory testing or both. When assessed in the field, the
     properties of the soil are estimated; precise description will always require laboratory testing to define soil properties.

     Where soil can be clearly identified as FILL this will be noled as the main soil type followed by a description of the composition of the fill (eg. FILL yellow-
                                                                                                                                                                  -




     brown, fine to coarse grained gravelly clay fill with concrete rubble). If the soil is assessed as possibly being fill this wHt be noted as an additional
     observation.


     Soils are generally described using the following sequence of terms. In certain instances, not all of the terms will be included in the soil description.


            MAIN SOIL TYPE (CLASSIFICATION GROUP SYMBOL)
            strength/density, colour, structure/grain size, secondary and minor components, additional observalions
            .




     Information on the definition of descriptive and classification terms follows.



                                                          SOIL TYPE and CLASSIFICATION GROUP SYMBOLS


                                            Major Divisions                Particle Size           Classification                     Typical Names
                                                                                                   Group Symbol
                                      BOULDERS                               > 200mm


                                      COBBLES                              63-20Omm
                                      GRAVELS                           Coarse: 20    -   63 mm         GW          Well graded gravels, gravel-sand mixtures, lillle
     COARSE                                                                                                         or no fines.
                                    (more than half of coarse           Medium: 6 20 mm
                                                                                     -




     GRAINED SOILS                  fraction is larger than              Fine: 2.36   -
                                                                                          6 mm          GP          Poorly graded gravels and gravel-sand mixtures,
                                    2.36 mm)                                                                        little or no fines, uniform gravels.
     (more than half of malerial is
     larger than 0.075 mm)                                                                              GM          Silty gravels, gravel.sand-silt mixtures.
                                                                                                        GC          Clayey gravels, gravel.sand-clay mixtures.
                                      SANDS                            Coarse: 0.6   -
                                                                                      2.36 mm           SW          Well grad~ sands, gravelly sands, little or no

                                                                       Medium:,0.2 0.6 mm                           fines.
                                      (more than half of coarse                       -




                                      fraction   is   smaller   than   Fine: 0.075    -   0.2 mm        SP          Poo~y graded sands and gravelly sands; Ille or
                                      2.36mm)                                                                       no fines, uniform sands.

                                                                                                        SM          Silty sands, sand-silt mixtures.
                                                                                                        SC          Clayey sands, sand-clay mixtures.
                                      SILTS & CLAYS                                                     ML          Inorganic sills and very fine sands, silly/dayey
                                                                                                                    fin.e sands or clayey silts with low plasticity.
                                      (liquid limit <50 %)
     FINE                                                                                            CL and CI      Inorganic clays of low to medium plasticity,
     GRAINED SOILS
                                                                                                                    gravelty clays, sandy clays, silty clays.
                                                                                                         OL         Organic sills and organic silty clays of low
     (more than half of material is
     smaller than O.S mm)                                                                                           plasticity.
                                      SILTS & CLAYS                                                     MH          Inorganic sills, micaceous or diatomaceous fine
                                      (liquid limit >50 %)                                                          sandy or silty soils.
                                                                                                        CH          Inorganic clays of high plasticity.
                                                                                                        OH          Organic clays      of medium       to   h h   plastiCity,
                                                                                                                    organic si~s.
                                      HIGHLY ORGANIC                                                     PI         Peat and other highly organic soils.

                                      SOILS




     Notes on Description and Classification of Soil
     Revision 2, November 2001                                                                                                                              Page 1 of2