Attachment B - Geotechnical Analysis

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•   Fill material will be subject to potential settlement post placement. Well compacted fill
    placed in accordance with AS3798 and otherwise, good earthworks procedure should
    typically be subject to settlement in the order of 0.5% to 1.0% of the fill thickness over a
    log cycle of time.

5.2 Site Classification
The results of the investigation, previous experience, and published correlations were used to
estimate the maximum characteristic ground surface movement (ys) value in accordance with
AS 2870. A suction change value of 1.2 was adopted along with a suction zone (Hs) of 1.5 m
were used in the calculations. In addition to this, the cracking depth was nominated to be
0.5Hs.


The results of the calculations indicate that at the time of the investigation, a ys value
approximately equal to <20 mm is considered suitable.


It is important to understand that numerous things can affect and consequently increase or
decrease the ys value for a site.


The following are items that may affect the site and as a result change the site classification to
a “Class P”.
•   Excessive moisture as a result of poor drainage, maintenance to drainage structures,
    excessive watering of gardens;
•   Placement or removal of vegetation that draws moisture from the soil surrounding the
    structure;
•   Additional earthworks outside the limitations set out in AS2870;


Long term maintenance is typically required for sites for maintenance. Useful information is
attached which should be read and understood by both the builder and property owner.

5.3 Foundations
It is recommended that all high level footings have perimeter, column and load bearing
footings found a minimum 0.3 m below surface levels. Where footings found into medium
dense (or stronger) sand, they may be dimensioned for a maximum allowable bearing pressure
of 100 kPa. All foundation excavations should be inspected by a suitably experienced and
qualified geotechnical engineer prior to the placement of concrete to confirm ground
conditions.




09 Feb 2021                                                         Proposed Residential Dwelling