Acid Sulfate Report

                              25 EDWARD STREET, NOOSAVILLE
                              PROPOSED DUPLEX DEVELOPMENT




                             Text Figure 7: Footing depth required to prevent undermining
Footing bases must be cleaned following mechanical excavation to expose undisturbed materials over the
full base area. It is recommended that footings be inspected by an experienced engineer prior to placement
of steel reinforcement to confirm allowable bearing pressures and cleanliness of excavations.
If any soil conditions encountered during construction are found to differ from those notes in the geotechnical
investigation, Tectonic should be notified immediately and an inspection carried out to determine if changed
to footing design are required.

5.3        Retaining Wall Design
Design for retaining walls could be carried out based on the parameters listed in Table 2. These values do
not include allowance for hydrostatic pressures nor transient (e.g. construction) or adjacent footing loadings.
Table 2: Retaining Structure Design Parameters

                                                                Lateral earth pressure coefficients
                             Unit      Friction
 Retained material          weight      angle
                                                            Ka                     Ko
                            (t/m3)    (Degrees)                                                       Kp
                                                     (Cantilever wall)     (Non-yielding wall)


 Loose Sand                  1.8          27                  0.4                  0.5                2.6


 Medium Dense (or
 Denser) Sand/Gravel
                             1.9          34                  0.3                  0.4                3.5
 (e.g. future controlled
 fill)



5.4        Permanent Drainage
Adequate site drainage must be installed to ensure that surface water runoff is directed away from
pavements and footings.

Subsurface drainage must be installed behind retaining walls in order to prevent the development of
hydrostatic pressure (e.g. slotted ‘aggi’ pipe wrapped in filter ‘sock’ placed in gravel backfill).
Subsurface disposal/infiltration of stormwater is not recommended due to the potential to affect the
performance of buildings footings and pavements. All excess stormwater should be piped or channeled
towards the local drainage system along Edward Street.




25 August 2017
Report No. 17265-001-Rev0                                 8