271117 Techtonic GeoTech Cooroy Mtn Rd

Mr Ken Freeman                                                                                     17385-001-Rev0
                                                                                                 27 November 2017




                                                                                    Lot boundary




          Existing house


Text Figure 1: Aerial image of area from 2016 (courtesy Noosa Shire Council Interactive maps website)


Based on our review of the proposed development concept plan , email correspondence from JTC
Engineers (the civil/structural engineers for the project), and from conversations with the client on site, it is
understood that the proposed work will include the construction of a porte cochere near the entrance to the
house, a carport to the west of the house, and an extension to the existing garage.

A possible two-storey extension is also being considered on the eastern side of the existing house,
comprising additional rooms, a cantilevered pool, and rooftop garden. We have been advised by JTC that
this is to be constructed using suspended floor slabs, and reinforced core filled blockwork. Cut and fill
earthworks will be required to construct a building platform.
 Earthworks comprising placement of about 2 m of fill above existing ground level will also be undertaken
on the northern side of the house to create a levelled area for a golf putting green. The fill embankment will
be retained by terraced retaining walls having a maximum overall height of 2 m. The existing swimming
pool located in this area is proposed to be infilled, with no demolition of the pool shell currently proposed.


1.2    Method and Scope of Investigation
As part of our slope stability assessment, a desk-top study was carried out comprising a review of
published geological maps, publicly available site information and a ‘soil test’ report prepared by Bowler
Geotechnical (Sunshine Coast) Pty Ltd (Bowler) for the original construction of the house (Bowler Job No
4095, dated 30 August 2004).

A walk-over survey was conducted in order to make an appraisal of the site conditions in regard to
topography, drainage, vegetation cover, geology, erosion, condition of any existing structures, and to look
for surface indicators of existing slope instability. The walk-over survey was carried out by an
experienced engineering geologist from Tectonic on 9 November 2017. The results of the desk top study
and site walkover are summarized in Section 3 below.

Tectonic also undertook a subsurface investigation in the proposed development areas, comprising the
excavation of six test pits using a six tonne excavator that was supplied by the client. The test pits were
excavated to depths of between 1.2 m and 2.8 m below ground level (BGL), and the majority were
terminated where bucket refusal was reached on rock. Pocket penetrometer testing was undertaken in
test pit sidewalls and on excavated undisturbed blocks of cohesive soil to help assess soil
strength/consistency. Rock strength was qualitatively assessed by observation of excavation
characteristics and using a geologists pick. The local geology and subsurface conditions are discussed




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