Rfi - PG-2096, 2022-11-03, Gr Ver 3

 Project No. PG-2096                                                                                                    Page | 5
 March 2023
 Ref: PG-2096, 2022-11-03, GR VER 3
 Keith & Jeannette Ince – Geotechnical Stability Assessment - Proposed Residence, 22 Arakoon Crescent, Sunshine Beach




4.0 GEOTECHNICAL MODEL

The subsurface profile encountered in the boreholes consisted of initially very loose to
loose sands overlying medium dense to dense sands to the termination of testing. In
Borehole 1, 600mm of very loose gravelly sand was encountered.

The density of the sand has been interpreted on the basis of the DCP testing results.

Detailed borehole record sheets are appended to this report.

Groundwater or subsurface seepage was not encountered in the boreholes at the
time of drilling.

5.0 EARTHWORKS AND SITE PREPARATION CONSIDERATIONS

Earthworks are expected to comprise of a cut operation of up to 4m to create an
underground plant room and water tank. Minor filling removed from the excavation
and primarily adjacent Arakoon Crescent is expected.

Consideration should be given to maintaining the stability of the excavation
immediately adjacent Arakoon Crescent during earthworks.

It is recommended that the following site preparation and earthworks procedures be
carried out as part of the earthworks procedures during development.

     •     All earthworks operations should be carried out in general accordance with AS
           3798-2007 "Guidelines on Earthworks for Commercial and Residential
           Developments".
     •     Trafficability across the site at the time of the investigation was assessed to be
           poor due to the steepness of the site.
     •     All topsoil (i.e. soil containing organic matter) and soils containing deleterious
           matter should be stripped from the construction area at the commencement
           of the earthworks operation.
     •     The majority of the soils on site will be suitable for re-use as structural fill, provided
           material is free of organic matter and deleterious material. It is likely that the
           soils require conditioning to bring the soils to optimum If the soils were overly
           moist, difficulty in achieving compaction of the materials will be encountered
           and moisture conditioning will be required.
     •     Imported fill should be of fair to good quality with a minimum Soaked CBR value
           of 10%, a maximum Iss=1.0% and a maximum particle size of 75mm or a ‘clean’
           sand.
     •     All filling should be undertaken in layer thicknesses of approximately 250mm (or
           as appropriate for the compaction equipment being used). Fill should be
           compacted to a minimum dry density ratio of 95% Standard in accordance
           with AS1289 5.1.1 or a minimum density index of 65% in accordance with
           AS1289 5.6.1.