Sunshine Butterflies - Attachment D - 010816-2

                              OUR BACKYARD
                              468 MCKINNON DRIVE, COOROIBAH

1.0       INTRODUCTION
This report details the results of a geotechnical investigation undertaken for the Our Backyard project at
468 McKinnon Drive, Cooroibah. The investigation was performed by Tectonic at the request of Tod
Consulting. Sunshine Butterflies is the client for the project.
The geotechnical investigation comprised drilling of boreholes at eight locations followed by laboratory
testing of soil samples. This report summarises the results of the investigation and includes
recommendations regarding earthworks, retaining structures, footings, drainage, site classification,
pavement design and on-site effluent disposal.

2.0       PROPOSED DEVELOPMENT
A master plan for the project is shown in Text Figure 1 below. It is understood that new sheds are proposed
to the north and south of the existing house, together with new internal pavements for car parking and
driveways. The existing septic system is to be replaced. It is understood that some widening of McKinnon
Drive is required to enable vehicle turning.




                                      BH2
                        BH1




                                                      BH3

    BH7

                                                    BH4
                            BH5        BH6

                            BH8A/B

Text Figure 1: Proposed layout plan of site (and borehole locations)


3.0       METHOD OF INVESTIGATION
3.1       Fieldwork
Investigations comprised drilling of eight boreholes (designated BH1 to BH8) to depths of up to 1.2 m below
ground level (BGL) using hand auger equipment. Borehole BH8 comprised two shallow boreholes on the
northern and southern sides of McKinnon Drive, being boreholes BH8A and BH8B, respectively. Dynamic
cone penetrometer (DCP) testing was conducted adjacent to boreholes BH1 and BH5.
Disturbed and undisturbed (U50 tube) soil samples were taken from the boreholes for laboratory testing,
including bulk samples from the likely pavement subgrade materials for California Bearing Ratio (CBR)
testing.
All boreholes were backfilled with spoil to the surface upon completion. The fieldwork was undertaken by an
experienced geotechnical engineer from Tectonic on 14 April 2016. Reports of boreholes, along with
explanatory notes, are presented in Appendix A. Borehole locations are shown in Text Figure 1 above.


4 May 2016
Report No. 16081-001-Rev0                              1