Soil Test & Footing Report SCG 30002(S)

3     SITE DESCRIPTION

The construction area has a gradient in the order of 4%.

Vegetation on the construction area (and nearby surrounds) consists of grasses and scattered trees.

The trees are located adjacent the proposed construction site.

The existing surface drainage is poor and sub-surface drainage is poor.


4     FINDINGS

The soil profiles encountered are shown on the attached borelog sections.

In our opinion the seepage at the base of our test sites indicates that at this level, we are approaching the water
table.

Furthermore, it is possible that this water table will fluctuate within the critical zone of any footing constructed in
this section of the soil profile. If excavations are initiated when the water table is high, considerable on-site
problems with seepage into excavations may occur and trench collapse may be significant.

This seepage may also cause collapse of excavations. If excavations are not filled with concrete as soon as they
are completed, there may be softening or collapse in the exposed soil profile, which may result in additional clean
out and increased concrete volumes. Temporary shoring or similar maybe required.

The sandy soils encountered are susceptible to collapse when unconfined. This may effect excavations and
result in additional earthworks and increased concrete volumes. Temporary shoring or Forma-Tube may be
required to retain the sands prior to concreting.

The samples classified on-site were assessed as having negligible plasticity, therefore laboratory testing was
considered unnecessary.

We have assessed the expected differential movement of the soil profiles encountered to be the equivalent of a
site with a Ys of less than 20mm.

For buildings within the scope of AS 2870-2011 a maximum allowable bearing pressure of 100 kPa is available
within the natural soils at the following depths:

                                 Test Site 1 – 600 mm             Test Site 2 – 500 mm

The following foundation material will provide a safe bearing capacity (100 kPa) for buildings within the scope of
AS 2870-2011 and is shown shaded on the attached logs;

           FOUNDATION MATERIAL - NATURAL MEDIUM DENSE SILTY SAND

5     SITE PREPARATION DETAILS

We recommend scraping this site free of all organic material and debris. The proposed construction areas should
then be levelled suitable for the construction of a block base. The bases must be filled with a clean granular
material such as sand, crusher dust or deco rock. The fill is to be free of organic material and have no clay
content. The fill shall not exceed 600mm in depth and is to be wetted and compacted in 150mm layers with a
vibrating plate making 6 passes (3 in each direction). Temporary back propping to the block base should be
provided throughout the compaction process. The compaction is to be sufficient to achieve a blow count of 7
blows per 300mm with an approved Perth Sand Penetrometer. Test results must be presented for approval prior
to commencing slab preparations.

Where a retaining wall is required, a cut batter of 1 to 2 (vertical to horizontal) in the sand profile taken from the
base of the proposed wall should be excavated. These earthworks must incorporate shallow surface spoon
drains at the base and along the high side of the cut. Drains must have an efficient outflow down-slope and clear
of the construction area. The exposed face should also be protected against the potential for stormwater erosion.
Should these recommendations be un-achievable the builder should seek guidance from this office on temporary
shoring, benching or other suitable techniques.


      SCG Consulting Engineers                                2                                     SCG Ref: 30002(S)