Attachment 4 - Geotech Report · MCU23/0030

                               50 NOOSA PARADE, NOOSA HEADS
                               PROPOSED RESIDENCE

5.4           Geotechnical Laboratory Testing
Table 2 summarises the results of geotechnical classification laboratory testing conducted on a soil sample
recovered from borehole BH2. The laboratory test certificate is presented in Appendix B.
Table 2: Summary of Geotechnical Laboratory Testing
                                           Particle Size Distribution                   Atterberg Limits
  Borehole
                  Depth (m)
    No.                            Fines        Sand Content         Coarse           Plasticity      Liquid
                                Content * (%)      ** (%)        Fraction *** (%)     Index (%)      Limit (%)

        BH2        2.6 – 3.0          7               93                93              N/P              -
Note:     *       Fines Content is the percentage of clay/silt fraction in the soil sample
          **      Sand Content taken as % retained on 0.075 mm sieve less % passing 2.36 mm
          ***     Coarse Fraction taken as % retained on 2.36 mm sieve.
          N/P     Denotes Non-Plastic
Laboratory testing of the sample from borehole BH2 indicates that the material tested comprised silty sand
with non-plastic fines.


6.0       ENGINEERING ASSESSMENT
6.1           Earthworks
Architectural drawings indicate that the proposed residential structure will include a single level basement,
with two storeys above. Bulk excavations for the basement are expected to extend to around 3 m depth, and
excavations to around 2 m depth will also be required locally for the pool to the north of the residence.

6.1.1           Site Preparation

Following removal of the existing building, pavements and associated elements, together with clearing of
vegetation; all tree stumps, footings and remnant internal services should be ‘grubbed out’. Any organic rich
topsoil should then be stripped and set aside. Organic topsoils and garden soils must not be re-used as
structural fill (off-site), however may be retained on site for later use across landscaping areas, if required.

6.1.2           Excavations

Excavations for the basement in the order of about 3 m BGL are expected to be mostly within relatively loose
to medium dense sands (fill and natural), with some firm sandy clay. Excavations to the design level should
be achievable using medium to large (14 to 30 tonne) excavators with toothed bucket attachments.
The standing groundwater table was recorded during the investigation at around 1.8 m to 2 m BGL. Depth to
groundwater may vary and is expected to be largely influenced by rainfall patterns and the adjacent river
level which is tidal. Excavations for the basement are therefore expected to extend into the groundwater
table and, considering that the basement excavations will be relatively close to the eastern and western site
boundaries, battering is not likely to be feasible. Temporary shoring of the excavation will be required and is
discussed in Section 6.2.
The pool excavation will encroach close to groundwater level and consideration should be given to raising
the level of the pool so as to avoid intersecting the groundwater table, otherwise temporary retention may
also be required for the pool excavation.




2 February 2023
Report No. 22500-001-Rev0                               7