Geotehnical Investigation Report · OPW22/0140

                                             PROPOSED UNIT DEVELOPMENT
                                             37 BOTTLEBRUSH AVENUE, NOOSA HEADS

To replicate future landscaping, a surcharge load of 5 kPa has been applied upslope of the proposed
building. Although building loads were not available at the time of reporting; a gross building load of 30 kPa
has been applied to areas of the building likely founded using high-level footings. Other areas will be
supported by piled foundations in the underlying medium dense (or denser) natural sands.
Soil shear strength was based upon effective parameters which were estimated based on our interpretation
of the subsurface investigation results, while also considering the values recommended for similar materials
in Appendix D of Australian Standard AS4678-2002 Earth Retaining Structures. Adopted soil parameters
are shown on the Slope/W output presented in Text Figure 9. Analysis was undertaken for a specified range
of entry and exit points that could impact the proposed development.

The analysed profile represents the critical section for the proposed development, which covers the deepest
proposed cut. Our analysis indicates that stability of the site hinges on the temporary and permanent
retention systems. Provided that those walls/structures are adequately designed and constructed the
proposed development will achieve at least the required minimum FOS for long-term stability (i.e. >1.5).

It should be noted that this modelling addresses the global stability of the proposed works; however, the
stability of the retaining walls must be addressed by others as part of detailed design.




                                                                       1.9
                                                                                                                               5 kPa Surcharge




                                                                             30 kPa Surcharge




    0                             10                              20                             30                              40                    50
                                                                             Distance (m)
  M aterial s
                          Name: Very Loose/Loose Sand         Uni t Wei ght: 18 kN/m³    Cohesion': 0 kPa       Phi ': 30 °   Pi ezom etric Li ne: 1
    Very Loose/Loose Sand Name: M edium Dense Sand          Unit Weight: 18 kN/m ³     Cohesi on': 0 kPa       Phi': 34 °   Piezometri c Line: 1
    M edium Dense Sand    Name: Dense Sand       Uni t Wei ght: 19 kN/m³     Cohesion': 0 kPa      Phi ': 36 °   Pi ezom etric Li ne: 1
    Dense Sand            Name: Retai ning Wal l   Unit Weight: 22 kN/m ³       Pi ezom etric Li ne: 1
    Retai ning Wal l




Text Figure 9: Slope/W output for long term conditions




13 May 2022
Report No. 22151-001-Rev0                                                                9