Preliminary Geotechnical Investigation · OPW21/0315

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The field work was undertaken by experienced geotechnical personnel who logged the bore, collected
disturbed samples for visual assessment and subsequent laboratory testing. Strata identification was
undertaken in the field through observation of cutting returns and recovered samples.


5.       Field Work Results

The subsurface conditions encountered in the bore are given in detail on the attached borehole log,
together with notes defining the classification methods and descriptive terms used. The depths were
measured below existing surface levels at the time of investigation.

The subsurface conditions encountered in the bore comprised relatively ‘loose’ to ‘medium dense’
sand fill to 2.35 m depth. In the absence of documentation to confirm the fill was placed in a controlled
manner or to confirm the degree of compaction to an engineering standard was achieved, the fill is
assumed to be ‘uncontrolled’. Underlying the fill, natural sands were encountered. Initially, the relative
density of the natural sands was medium dense, grading dense to very dense and then very dense
with depth.

Groundwater seepage was encountered at 2.35 m depth at the time of the investigation. It should be
noted however, that groundwater depths and ground moisture conditions are affected by climatic
conditions and soil permeability, and will therefore vary with time. Groundwater levels are expected to
be similar to the water level in the canal at the rear of the site, albeit somewhat a dampened response
to tidal variations.


6.       Laboratory Testing

Particle size distribution tests were carried out on selected samples recovered from the bore for
classification purposes. The results of this testing are summarised in Table 1 with detailed material
test reports attached.

Table 1: Results of Particle Size Distribution Testing

Bore        Depth             Material             Particle Size Distribution %
No.          (m)
                                               Gravel         Sand         Silt/Clay
     1     1.6-2.0           FILL/ SAND           0             97             3
     1     3.6-4.0             SAND               0             99             1


In addition, samples recovered from the bore were screened by measurement of pH after the addition
of distilled water (pHf) and peroxide (pHfox). The pHf test provides a preliminary indication of past
oxidation of sulfides resulting in the presence of actual acid sulfate soils (AASS). The pH fox test
provides a preliminary indication of the presence of unoxidised sulfides and therefore, potential acid
sulfate soils (PASS).




Proposed Residence                                                                      95120.00.R.001.docx
33 Wyuna Drive, Noosaville                                                                     October 2020