081128 - Lots 5 - 8 Soil Tests · OPW18/0155

                                 LOTS 5 TO 8, SETTLERS COVE, SERENITY CLOSE, NOOSA



                                     TRENCH BACKFILL
      GROUND LEVEL




                                                                  FOUND FOOTINGS
      TRENCH SIDEWALL                                             BELOW THIS LINE
                                                           45°


                                             1.0m
                                                    1.0m



       SEWER / STORMWATER PIPE

If any soil conditions encountered during excavations or piling are found to differ from those noted in the
geotechnical investigation, Golder Associates should be notified immediately, and an inspection carried out
to determine if changes to design are required.



5.4       Retaining Structure Design
The design of any retention system for this site should be conducted with due consideration of embedded
depth below the excavation level (ie. cantilever for sheet piles), variability in stratigraphy over the anchor
embedment length and anticipated ground conditions. Temporary support design must also take into
account the position of adjoining building foundations and underground services. It would be necessary to
gain permission from adjacent site owners and Noosa Council to install anchors below ground level into
adjoining properties.

Retaining structure design may be carried out using a triangular pressure distribution applicable to the wall
type (ie. active pressures for a cantilever wall or at rest pressures for a propped/anchored wall) and based
on the parameters in Table 3. The values in Table 3 assume that the walls are fully drained and no
allowance is included for construction loading, adjacent foundation loadings, the effect of sloping ground, or
backfill compaction stresses.
Table 2: Retaining Structure Design Parameters
Retained Material      Unit Weight   Friction              Lateral Earth Pressure Coefficient
                       (t/m3)        Angle (º)

                                                           Ka           Ko               Kp

Loose to Medium          1.8             28                0.36         0.5              2.7
Dense Sand



Compacted Fill           *               *                 *            *                *



Note: * Variable dependent upon the type of material used and the degree of compaction achieved.


Positive permanent drainage must be installed behind retaining walls.


December 2008
Report No. 087682058 002 Rev.1                         5