Reference Document - RAL25/0020 & OPW25/0194 (As Published)

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•       Topsoil/Fill: Firm to stiff sandy clay topsoil was encountered in the bores, except Bore 5, to
        between 0.1 m and 0.2 m depth. Underlying the topsoil in Bores 3 and 6 and from the surface
        in Bore 5, relatively ‘very dense’ sandy gravel fill was encountered to between 0.2 m and 0.3 m
        depth.
•       Sandy Silt/Silty Sand: Underlying the topsoil and/or the sandy gravel fill material, firm sandy
        silt was encountered in Bores 1, 3 and 5 along the eastern portion of the site to between 0.9 m
        and 1.15 m depth.
•       Silty, Sandy Clays: Underlying the above mentioned soils, silty and sandy clays were
        encountered in the bores. The strength consistency of the clays was generally very stiff, stiff
        locally in Bores 2, 4 and 6. The clays continued to bore termination at 3.0 m depth.

No groundwater seepage was observed in any of the bores at the time of drilling or prior to
backfilling. However, it is noted that the sandy silt was described as being ‘moist to wet’ in Bore 3.
It should be noted that groundwater depths and ground moisture conditions are affected by
climatic conditions, soil permeability, drainage conditions and human influence; and will
therefore vary time.


5. Laboratory Testing

5.1      Shrink-Swell Index

Shrink-swell index tests were carried out on ‘undisturbed’ samples from the bores. The results of
the testing are summarised in Table 1 with material test reports in Appendix D.

Table 1: Results of Shrink-Swell Index Testing

    Bore Depth           Material                     Shrinkage            Swell               Shrink-Swell Index
    No.  (m)                                          (%)                  (%)                 (% per ΔpF)
    1      0.8-1.03      Silty Sandy CLAY             2.1                  0.0                 1.2
    4      0.7-1.09      Silty Sandy CLAY             5.4                  0.0                 3.0

5.2      Plasticity and Particle Size Distribution

Samples recovered from the bores were tested in the laboratory for engineering properties of
plasticity and particle size distribution for classification purposes. The results of this testing are
summarised in Table 2 with material test reports in Appendix D.

Table 2: Results of Plasticity and Particle Size Distribution Testing

Bore       Depth       Material                        Plasticity                   Particle Size Distribution (%)
No.        (m)
                                                       LL     PL     PI     LS      Gravel       Sand          Silt/Clay
                                                       (%)    (%)    (%)    (%)
3          0.4-0.8     Sandy SILT/Silty SAND 18               -      NP     2.5     8            56            36
6          1.0-1.21    Silty Sandy CLAY                50     23     27     11.0    20           22            58
Where LL = Liquid Limit, PL = Plastic Limit, PI = Plasticity Index, LS = Linear Shrinkage, NP = Non-Plastic




Proposed Subdivision                                                                                    237894.00.R.001.Rev0
12-14 Gympie Street, Tewantin                                                                                  October 2025