102995-10 Permissible change request

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samples. On completion, the bores were observed for groundwater seepage and then backfilled with
spoil tamped into the holes.

The field work was undertaken by experienced geotechnical personnel who logged the bores,
collected disturbed samples for visual and tactile assessment.


3.     Field Work Results

The subsurface conditions encountered in the bores are described in detail on the attached borehole
logs. In summary the subsurface conditions encountered in the bores typically comprised filling to
between 4.1 m and 5.9 m depth. The filling typically comprised a gravelly sandy clay overlying a sandy
clay which was in turn underlain by a silty clay in Bores 2, 3, and 5. The filling was underlain by
natural sandy then silty clays.

No groundwater seepage was observed during the investigation; however, it should be noted that
groundwater depths and ground moisture conditions are affected by climatic conditions and soil
permeability, and will therefore vary with time.


4.     Comments

4.1    Appreciation of Ground Conditions

DP previously carried out geotechnical investigations on the site in 2006 and 2008. In the area of the
site, uncompacted to poorly compacted filling with foreign material (ie. bricks, timber, steel sheeting,
steel pieces, tree roots) was encountered up to 4.7 m depth. As mentioned above, filling was
encountered to between 4.1 m and 5.9 m depth in the recent bores. The near surface filling
encountered in the bores at the time of this investigation appear to be clean of any foreign, deleterious
material or topsoil material rich in organics or root matter. Any organics or foreign material including
concrete, plastic, wire and bricks encountered within the recent bores was encountered typically in the
sandy clay filling material below 1 m depth consistent with the ‘uncontrolled’ filling previously
encountered.

The settlement of ‘uncontrolled’ filling cannot be reliably predicted as it is unknown whether the filling
has been placed and uniformly compacted to an appropriate engineering standard. The presence of
voids within the ‘uncontrolled’ filling as well as potential soft/loose zones or inclusions of deleterious
materials may lead to potentially significant settlements, with possible large settlement over short
distances (ie. differential settlements) where looser pockets occur in the filling.

4.2    Recommendations for Future Construction

Given the above, future development on the site will need to be planned, designed and constructed in
accordance with sound and proper engineering principles, and more specifically take into
consideration the potential long term settlement or creep of the ‘uncontrolled’ filling.




Report on Geotechnical Investigation                                                       Project 33984.02
178 Eumundi-Noosa Road, Noosaville                                                         September 2015