Geotechnical Investigation

                             PROPOSED CALILE HOTEL NOOSA DEVELOPMENT
                             3 – 7 SERENITY CLOSE, NOOSA HEADS

6.2.2       Excavations
Excavations through the soils encountered in the boreholes should be achievable using conventional
earthmoving plant (e.g. small or larger excavators with toothed buckets). Temporary, unsurchaged cuts
could be formed at 1V:2H in the very loose to loose sand, and at 1V:1.5H in medium dense (or denser) sand,
for batters up to 4 m in height. Flatter batters or temporary retention may be required if groundwater seepage
is encountered or if sloughing of dry sand occurs at the batter surface. Deeper cuts, if required, should be
specifically assessed by Tectonic, unless supported by temporary retention measures.

Permanent cuts or fills greater than 1 m high must be retained. Permanent cut and fill batters up to 1 m high
shall not exceed 1V:2.5H. Any permanent soil and fill batters will require erosion protection (e.g.
revegetation or surface protection).

Due to spatial restraints and the depth of excavations proposed, temporary shoring will likely be required
(e.g. sheet piles) as per the recommendations in Section 6.4 below. Excavations in close proximity to
existing structures and infrastructure (e.g. sewer main and stormwater infrastructure through the central part
of the site), including on neighbouring properties, will need to be specifically designed to prevent
undermining. It is recommended that existing pipe invert levels be assessed by non-destructive pot holing to
assess the possibility of undermining. If undermining is a potential issue the existing structures may need to
be underpinned or excavations may require temporary shoring.

The advice of a suitably qualified and experienced structural RPEQ must be sought regarding any potential
undermining and design and construction of any underpins/temporary shoring (if required).

The above recommendations do not supersede any existing safety regulations or legislation applicable to
excavations (e.g. limits on personnel entry into trenches).

6.2.3       Filling
The natural sandy soils and existing sandy fill materials where free of deleterious materials (e.g. vegetation,
organics etc.) may be reused as structural fill, subject to appropriate moisture adjustment. It should be noted
that compaction of such relatively ‘clean’ sands as structural fill requires the addition of substantial volumes
of water (‘flooding’) combined with the use of vibratory compaction equipment (typically a smooth drum roller
or heavy vibrating plate).

Should importation of fill be required, it is recommended that such fill should comply with the following:

       Minimum CBR of 10%
       Maximum plasticity index of 15%
       Shrink-swell index ≤ 1%
       Maximum particle size of 100 mm

Any fill should be compacted at moisture contents within the range of ±2% of optimum moisture content for
Standard Compaction. Fill material should be placed in 250 mm thick (loose thickness) layers and be
compacted by repeated rolling using a minimum 4 tonne smooth drum roller (or equivalent, with vibration on
if safe to do so) to achieve a dry density ratio of at least 98% of the maximum Dry Density Ratio (DDR),
based upon the Standard Compaction method, or a Dry Density Index of at least 75%.
Confirmatory compaction testing must be carried out at regular intervals. A minimum of two tests per vertical
lift is recommended where structural fill heights are to exceed 300 mm. Further details for control and testing
of fill are given in Australian Standard AS 3798-2007 Guidelines on Earthworks for Commercial and
Residential Developments. We recommend that the fill be placed as a minimum under Level 1 testing, with
density testing conducted at a Type 2 frequency.

Fill embankment edges must be over-filled by 0.5 m (horizontally) and then trimmed back to well compacted
material.




7 October 2022
Report No. 22239-001-Rev0                              15