Appendix E_Geotechnical Investigation

                              PROPOSED UNIT DEVELOPMENT
                              PRECINCTS E2 & F, NOOSA SPRINGS

Any excavations required adjacent to existing structures, will need to be specifically designed to ensure that
the structures are not adversely affected (e.g. 'undermined').

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

7.2.3        Filling
Except for replacement of uncontrolled fill, it is expected that filling will be minimal (less than 1 m) for the
proposed development. The existing uncontrolled fill (where clear of vegetation or other deleterious
material) and natural soils are expected to be suitable for re-use as structural fill, subject to appropriate
moisture adjustment.

All fill should be compacted at moisture contents within the range of ±2% of optimum moisture content for
Standard Compaction. Fill particles greater than 100 mm must be excluded. Fill should be placed in
maximum 250 mm thick (loose thickness) layers and be compacted by repeated rolling to achieve a dry
density ratio of at least 98% of the maximum Dry Density Ratio (DDR) for building fill and 100% DDR for fill
within 0.3 m depth of pavement subgrades (all Standard Compaction method), or 75% of the Dry Density
Index for cohesionless fills (e.g. sands).

Confirmatory compaction testing must be carried out at regular intervals. Details for inspection and testing of
fill are given in Australian Standard AS 3798-2007 Guidelines on Earthworks for Commercial and Residential
Developments. We recommend placement of fill to Level 1 standard if fill is to support buildings.

Batters in controlled fill are to be formed no steeper than 1V:2H.

7.3       Building Foundations
7.3.1        Indicative Site Classification
Site classifications for footing design are determined in accordance with AS2870-2011 Residential Slabs and
Footings, and depend on the depth of cut / fill undertaken at a site, variations in the natural soil / rock depths
and reactivity of the in situ soil and any imported fill materials.

Based on the results of the investigation, the indicative site classification for this site is Class P in
accordance with AS 2870-2011 Residential Slabs and Footings, due to the existing steep slope and
uncontrolled fill. If not for the uncontrolled fill and steep slopes the site would have the characteristics of a
Class M site in accordance with AS2870. The estimated characteristic surface movement (‘ys’) at this site is
expected to range from 20 mm to 40 mm. It should be noted that the predicted order of movement is based
on the existing natural soil profile (i.e. no cutting or filling), and moisture content changes within soils due to
normal seasonal moisture variations only.

The site classification must be reviewed following finalisation of earthworks and building layouts.

7.3.2        Footing Design
Future buildings and associated structures on the ridge and flanks of the ridge shall be supported on piled
foundations (screw piles or open bored piles) taken at least 3 m into medium dense (or denser) sands.
Based on our investigation, founding depths are estimated to range between 3.8 m and 6.6 m BGL (existing
natural surface level).

Piles so founded may be designed using an allowable bearing capacity of 300 kPa.

Should open-hole bored pile construction be adopted, sidewall collapse due to the dry and very loose to
loose nature of the sands will likely be encountered within the top 1 m to 1.5 m of excavation, resulting in
‘belling out’ of the pile hole. To minimse over-excavation at pile locations a temporary steel liner could be
inserted during the drilling process to prevent side wall collapse. The casing could then be removed. The
casing could then be removed after the concrete pour and re-used. Alternatively, the pile excavation could
be allowed to ‘bell out’, with a ‘formatube’ type liner installed after reaching the target founding depth to
minimise the volume of concrete required. Excavated sand could be replaced around the ‘formatube’ after
pouring.



11 November 2015
Report No. 15193-002-Rev0                                13