08/0169 Information Response to DERM - 71 Seaview Terrace Sunshine Beach · 132008.169

                                                                 TODCON


      secure piled foundations approximately 10-12m further down slope. The
      western contiguous piled retaining wall could be more economically
      constructed using temporary tie-back ground anchors installed into the
      adjacent properties, but it may not be possible to obtain permission from
      those owners to do this.

      The combination of cantilevered and strutted contiguous piled walls
      throughout the building works will not only provide very stable working
      platforms during the construction stage, but will also greatly enhance the
      completed building's capacity to resist lateral loads and add significantly
      to the stability of all areas uphill of the proposed works by limiting the
      extent of any future surface sand slips.

      Once the contiguous piled walls are completed and fully strutted where
      required, the remainder of the reinforced concrete structure can be readily
      constructed on a safe and stable building platform using traditional
      formwork and cast-insitu methods.

3.2   General

      the proposed residence comprises the following:

      •     Two living levels to the main residence
      •     Access driveway at road level/roof level.
      •     External terraced areas, pool and access corridors

3.3   Site Conditions

      The information discussed below has been interpreted from the
      geotechnical reports by Morrison Geotechnical (dated September 2009)
      and SCG Consulting Engineers dated 24 March 2009.

      In brief, boreholes drilled across the site encountered fairly consistent
      tipper layer conditions comprising loose sands gradually increasing in
      density with depth. Deeper surface conditions vary across the site from
      dense sands to very stiff sandy clays overlying extremely weathered
      sandstone at approximately RL33.

      Ground water seepage and springs are likely to be encountered at any hard
      impermeable layers following wet weather.

      Due to the topography of the site all precautions must be taken to
      minimise risk of surface sand slips and possible flow of loose surface
      sands from excavated trenches and building platforms.

      Surface sands are very loose and slope at gradients of between 23° and
      32°.

      The additional Geotechnical information provided in the Morrison
      Geotechnical Report to 22.4m depth will be used to further develop the
      structural design, and refine construction procedures.

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