RFI - Attachment D - Geotechnical Investigation Report · MCU25/0053

                                                                                                    PTG/01608 – 0001 – Rev0


Acidity/Equivalent Acidity value that exceeded the criteria was 26 mol H+/t (near the top of BH1), and the highest
was 128 mol H+/t (near the base of BH3).

The pHfield, pHFOX and confirmatory CRS results indicate the presence of Acid Sulfate Soils (Possible Acid Sulfate
Soils) at the site within soils up to 4.5 mBGL (maximum investigation depth). Therefore, based on the test results, an
Acid Sulfate Soil Management Plan (ASSMP) will be required if this project in to proceed.



9 GEOTECHNICAL COMMENTS
The geotechnical comments in this report are based on factual information collected during the fieldwork, best
practice, local experience and published literature however are fundamentally opinion.

In summary, the ground conditions that are likely to be encountered at the site can be characterised as comprising a
surficial layer of topsoil, then silty sand/sand. Localised uncontrolled fill zones could also be encountered.


         SITE CLASSIFICATION AND SITE MOVEMENTS
In accordance with AS2870, the site is classified as class ‘A’ due to the ground conditions being sand with little or no
ground movement from moisture changes to be expected.


          FOUNDATIONS
Based on an interpretation of the typical structural loads anticipated, and subsurface conditions encountered during
the investigation, both high level and piled foundations could be considered suitable for the development.

Based on the information available at the time of writing this report, general design parameters and recommendations
have been provided in the subsections below which can be used for design of the foundation system of the structure.
The design of the structure must consider the structural loads against serviceability.

All footing excavations should be inspected by PTG to confirm that bearing pressures have been achieved, and
footings are clean and free from loose and/or water softened materials.


         9.2.1 HIGH LEVEL FOUNDATIONS
Preliminary design of high-level pad footings up to 3 m wide or strip footings with a minimum 0.5m depth can be
designed using the allowable bearing pressures in Table 2. Elastic settlements of properly designed and constructed
high level footings are usually in the order of 10 mm for 0.5 m wide strip footings to 25 mm for large square pad
footings up to 3 m wide.

Table 6: Allowable Bearing Pressures for High Level Footings
                        Material Type                                  Allowable Bearing Pressure (kPa)
                    Loose sand/silty sand                                      Not Recommended
               Medium dense sand/silty sand                                             100
                    Dense sand/silty sand                                               150

Note that in sands, bearing capacity increases with depth. If foundation depths for the basement are provided, then
updated parameters can be provided.


         9.2.2 PILED FOUNDATIONS
Bored or driven piles can be designed using the ultimate skin friction and base bearing capacities in Table 7 below.




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