OPW052025 Report - Part 2

In situ soil strength was assessed using a pocket penetrometer in test pit sidewalls (where safe access
permitted), and otherwise in relatively undisturbed ‘block’ samples recovered in the test pit spoil.
Small, disturbed samples were recovered in selected horizons from the test pits. The test pits were
backfilled progressively to surface at the time of the investigation, with excess spoil mounded at surface.
Reports of the test pits, along with explanatory notes, are presented in Appendix A. Test locations are
shown in Figure 1, attached at the conclusion of the report text.


3.2           Laboratory Testing
Selected soil samples was dispatched to Chadwick Geotechnics, a NATA accredited laboratory located in
Birtinya for geotechnical testing. Laboratory testing was undertaken in accordance with Australian
Standard AS1289 Methods of Testing Soils for Engineering Purposes and comprised:
▪    One Shrink-Swell Index test for site classification purposes at the house site; and
▪    One single point, four day soak California Bearing Ratio (CBR) test for pavement design purposes.
Laboratory test results are discussed in Section 4.3. The laboratory test certificates are provided in
Appendix B.



4.            Site Description
The subject site is formally described as Lot 3 on RP849389 and covers a total area of 56.7 ha. The site
consisted mostly of moderately sloping ground, with a significant area cleared for pastoral activities.
Sporadic trees were present to the centre and north of the site, with denser vegetation over steeper
ground to the south-western corner of the block. A mixture of similar rural allotments and pastoral
blocks were located in the surrounds. Middle Creek Road provides access from the eastern/north-eastern
frontage, and the gazetted (although undeveloped) road corridor for Black Mountain Road was located
to the west/south-west. A relatively recent aerial image of the site is shown in Text Figure 2 below.



                                                                                         Existing sheds



                            Approx. Lot boundary                                                 Middle Ck Rd




                                                                           Proposed driveway along existing
                                                                           track


                                                           Approx. proposed house site



                                                          Black Mountain Road corridor

         Text Figure 2: May 2024 aerial image of lot and surrounds (courtesy Queensland Globe)



Geotechnical Investigation & Slope Stability Assessment
9 April 2025 | 25050-001-Rev0                                                                                   3