Geotech 95141.00.R.001

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during construction. Should heavy compaction be required, then wall stresses will be well in excess of
Ko and temporary propping should be used.



6.6    Indicative Pavement and Slab-On-Ground

Based on the DCP testing, insitu CBR values for the upper very loose to loose sand (albeit
uncompacted) at the current relative density and moisture conditions is typically less than 3%.

Provided site and subgrade preparation is carried out in accordance with this report and allowing for
minor variations in subgrade type and strength, it is recommended that a design CBR value of 5% or a
modulus of subgrade reaction of 35 kPa/mm be adopted for the upper sands.

Rigid pavements should be designed using a soil modulus of 25 MPa for short term loads and 20 MPa
for long term loads.

For composite subgrades (ie. where imported filling is less than 1m) the Japan Road Association method
of assessing a weighted subgrade strength should be used:

       CBRW = (DF x CBRF0.33 + (1-DF) x CBRS0.33)3

       where:         CBRW = weighted subgrade CBR (%)
                      DF = depth of filling (m)
                      CBRF = CBR of filling material (%)
                      CBRS = CBR of natural subgrade (%)

On-ground building floor slabs (ie. floating slabs) should be detailed so they can accommodate potential
ground movements, including settlements. Differential settlements could be expected to vary across the
site, depending on the floor loads, as well as the thickness and consistency of the near surface soils.
Dowelling of floor slabs will minimise differential movements between adjacent slabs.




7. References

AS 2159. (2009). Piling - Design and Installation. Standards Australia.
AS 2870. (2011). Residential Slabs and Footings. Standards Australia.
AS 3798. (2007). Guidelines on Earthworks for Commercial and Residential Developments. Standards
Australia.
AS 4678. (2002). Earth-retaining structures. Standards Australia.




 Geotechnical Investigation, Proposed Youngcare Facility                               95141.00.R.001.docx
 32 Viewland Drive, Noosa Heads                                                               January 2021