Slope Stability Analysis

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                                                                                                        arcosgroup.com.au
                                                                                       Sunshine Coast | Brisbane | Gold Coast




 The design of retaining walls should be undertaken by a suitably qualified RPEQ engineer. Retaining walls must
  be designed to achieve a minimum safety factor of 1.5 against global instability.
 Avoid leakage from underground services and drains. Any leaking services or blocked drains should be remedied
  promptly.
 Erosion protection of cut and fill batters will be required. Batters should incorporate crest and toe drainage. Batters
  should be vegetated appropriately to minimise erosion.
 Overland flow paths will need to be carefully directed to approved outlets to minimise erosion possibility.

8         GEOTECHNICAL RECOMMENDATIONS
The following sections details specific geotechnical constraints or recommendations in addition to general hillside
construction notes.


8.1       FOOTINGS
In accordance with industry standards, a geotechnical engineer from Arcos should undertake the testing within the
footings to confirm that the encountered material is in alignment with the adopted parameters and assumptions
provided within this report. Where this does not occur, Arcos cannot be held liable for any of the information presented
within this report.
All footings will need to be designed to accommodate potential ground surface movement, settlement values and
any additional settlement values associated with the placement of new fill.
Settlement for suitably sized and designed high level footings should be in the order of 1-2% of the width of the
footing.
If footings are located adjacent to an underground service or other obstruction that is not homogenous with the
founding strata, the footing should be extended a minimum 0.3 m below an imaginary line projected at a 45 degree
angle from the lowest point of the service/obstruction. This is depicted graphically for reference:




Where footings found into stiff (or stronger) clays, they may be dimensioned for a maximum allowable bearing
pressure of 100 kPa.
The ultimate geotechnical end bearing and shaft adhesion parameters are presented in Table 2 for deep level
footings where high level footings are not suitable. The values given will need to reduced by applying a suitable
geotechnical strength reduction factor (Φg) for limit state or divided by a suitable factor of safety for working stress
methods. The Φg should be selected by the designer.



Sunshine Coast | Brisbane | Gold Coast