Reference Document - RAL25/0020 & OPW25/0194 (As Published)

                                                                                               Page 7 of 15




•     Depressions formed by the removal of existing structures, underground elements,
      vegetation etc. should have all disturbed, weakened soils excavated out and then backfilled
      with approved fill well compacted in layers to the same requirements as for the overlying
      layers of fill.
•     It is considered that the majority of materials won from excavations on site where free of
      organic and deleterious material will generally be suitable for reuse as bulk fill provided the
      moisture content of the soils on placement approximates the OMC.
•     Imported fill material, if required, typically should be a good quality select fill material of low
      to medium plasticity and well graded with a maximum particle size of 75 mm.
•     Approved structural fill should be placed in layers not exceeding 0.3 m ‘loose’ thickness, with
      each layer compacted to a minimum dry density ratio of 95% relative to Standard
      compaction. Unbound pavement gravel should be compacted to a minimum dry density
      ratio of 100% relative to Standard compaction. Where fill has significant clay content,
      moisture content within the fill should be maintained within 2% of OMC during and after
      compaction until covered with subsequent layers.
•     Care should be taken not to use over-wet clayey soils as this can lead to problems associated
      with trafficability and workability. Clayey soils should also not be over-compacted (ie. not
      more than 102% Standard) or placed too dry of OMC, as this can lead to future swelling and
      softening with changes to moisture content or inundation from water.
•     Field density testing should be carried out to confirm the standard of compaction has been
      achieved and the placement moisture content. The frequency of testing should be carried
      out in accordance with AS 3798 (2007) and distributed reasonably evenly throughout the full
      depth and area of filling.
•     Level 1 inspection and testing of filling must be undertaken where the fill is to support
      buildings or pavements. It is also recommended that Level 1 inspection and testing be
      adopted for all trench backfill greater than 1.5 m deep in areas to support buildings or
      pavements as settlement of deep trench backfill can have significant impact on these works.

The above procedures will require geotechnical inspection and testing services to be employed
during construction by an experienced and competent geotechnical testing authority with an
experienced geotechnical engineer to overview the work and provide further advice where
required. It is recommended that earthworks inspection and testing services that will be required
during construction be carried out by Douglas.

6.3    Excavation

It is estimated that the excavation of soils encountered on site could be undertaken using small
to medium sized earthmoving equipment, such as drotts or D6 dozer, backhoes or 8-15t (or larger)
excavators.

The use of pneumatic tools or hydraulic rock breakers will be required to assist in the excavation
of any existing concrete slabs and/or footings (if encountered).

It should be recognised that the excavatability estimates are based on materials encountered at
the bore locations only and that conditions may prove more difficult (or easier) for excavatability
beyond the bore locations and the depths excavated as part of this investigation. This information
is also based on past experience and reference to published literature and should only be taken




Proposed Subdivision                                                                   237894.00.R.001.Rev0
12-14 Gympie Street, Tewantin                                                                 October 2025