ECM_22343520_v1_Geotechnical Investigation · 132000.200173.1

                                          PROPOSED RENOVATIONS
                                          2 ARAKOON CRESCENT, SUNSHINE BEACH

            It is likely that the above temporary batter slopes will not be able to be achieved, at least along the western
            boundary, due to spatial restraints, and so temporary shoring may be required (e.g. sheet piles) as per the
            recommendations in Section 6.3 below. Excavations in close proximity to existing structures and
            infrastructure (e.g. underground services), including on neighbouring properties, will need to be specifically
            designed to prevent undermining. It is recommended that footing exposures or confirmation of existing
            foundations via certified building plans be undertaken 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).

            6.1.3         Filling
            The natural sandy soils where free of deleterious materials (e.g. vegetation, organics etc.) may be reused as
            structural fill (retained under the building), 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

            The primary recommendation would be to re-use site won material, or use a similar granular soil where
            import is required. 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 95 % of the maximum Dry Density
            Ratio (DDR), based upon the Standard Compaction method, or a Dry Density Index of at least 70 %.

            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.

            6.2         Building Foundations
            6.2.1         Indicative Site Classification
            Site classifications for footing design are determined in accordance with AS 2870-2011 Residential Slabs and
            Footings, and depend on the depth of cut / fill undertaken at a site, variations in the natural soil/rock depths,
            and the reactivity of the in situ soil / rock and any imported fill materials.

            Based on the results of the investigation, the site is classified as Class P in accordance with AS 2870-2011
            Residential Slabs and Footings, due to the presence of poor bearing capacity soils at shallow depths, and
            trees. If not for these factors, the site would have the characteristics of Class S, with the estimated
            characteristic surface movements (‘ys’) ranging up to about 20 mm. However, due to the potential variability
            in subgrade density a site classification of Class M is recommended in relation to assessment of flexibility
            requirements for ground slabs, footing and plumbing design.




             24 February 2023
             Report No. 22484-001-Rev0                              15
Document Set ID: 22343520
Version: 1, Version Date: 16/03/2023