Compiled Reference Documents - MCU25/0091 (As Published)

            Wingara Hills Pty Ltd

            7.3.1 Site Classification
            The site classification was derived in accordance with Australian Standard AS 2870 Residential slabs and
            footings which provides an indication of the likely magnitude of reactive (shrink and swell) movements
            associated with normal seasonal soil moisture variations.
            The subsurface profile encountered in the test pits at the proposed cabin locations comprises primarily stiff
            (or stiffer) silty clay (residual soil) of low to medium plasticity and overlying weathered material and/or
            mudstone.
            A preliminary site classification of “Class H1” (in accordance with AS2870-2011) is recommended for such
            site conditions. Laboratory testing will be required to confirm the site classification. If cut to fill works are
            proposed this may alter the site classification and Core should be consulted.
            It should be noted that the estimated order of movement is based on the existing soil profile and the
            proposed founding conditions, including moisture content changes within soils due to normal seasonal
            moisture variations only.
            As the site soils are anticipated to be ‘reactive’, it will be necessary to ensure that ‘usual good practice’ is
            adopted for design and detailing if control of reactive ground movement is desired. Such practices should
            include the following:

                    Trees and shrubs should not be planted or be allowed to remain closer than their mature height to
                     movement sensitive features.

                    Soil moisture should not be allowed to change during or following construction.

                    Site grades should be designed to readily shed water and prevent ponding around footings and other
                     movement sensitive areas.

                    The proposed buildings should be made as “flexible” as possible to cope with reactive soil movements.

                    Services beneath the buildings should be kept to a minimum and should be designed to be flexible
                     (especially at building walls), and to prevent any leakage.

            7.3.2 High Level Footings and Piers
            Building loads could be supported by strip or pad footings taken into stiff (or stiffer residual clays or deeper
            into extremely weathered material or mudstone (depths expected to be about 1 m to 1.5 m bgl).
            The following allowable bearing pressures may be adopted in natural materials for design purposes:
                 -      Shallow footings on Stiff (or Stiffer) Clays                      100 kPa
                 -      Shallow footings on Very Stiff/Hard Clays                         200 kPa
                        Extremely Weathered Material
                 -      Bored piers are founded in Extremely Weathered Material/          500 kPa
                        Weathered Mudstone

            To achieve the recommended allowable bearing pressures, founding materials must be dry and cleaned of
            any loose, disturbed or saturated materials prior to pouring concrete. Footing excavations must be inspected
            by an engineer from Core to confirm the foundation material meets the design pressure requirements.
            If any soil conditions encountered during the footing excavations are found to differ from those noted in the
            geotechnical investigation, Core should be notified immediately, and an inspection of the footing excavations
            should be carried out to assess if changes to footing design are required.
            All proposed footings should found such that they are not adversely affected by any adjacent excavations,
            batter slopes, trenches, or retaining walls that are not designed to support building or fill loads.
            To minimise the potential for any adverse interaction effects, footings should found at least below a plane
            extending 1 m horizontally from the base of trenches/batter slopes/excavations/ retaining walls, then rising
            up at 1V:1H. This requirement is illustrated in the following diagram.


            J002915-001-R-Rev0                                     10


Document Set ID: 24031832
Version: 1, Version Date: 14/08/2025