MCU14/0024 - Response to Information Request - Attachment 4

3 SITE DESCRIPTION

The construction area has a gradient in the order of 26%.

Vegetation on the construction area (and nearby surrounds) consists of scattered trees.
The trees are located on and adjacent the proposed construction site.

The trees are of a height and proximity that could affect the moisture conditions within the proposed
construction site. Refer to the appendices to the rear of this report for guidance on Trees and Construction.

The existing surface drainage is good and sub-surface drainage is good.

4 FINDINGS

The soil profiles encountered are shown on the attached borelog sections.

No water table was encountered during our testing program.

The sandy soils encountered are susceptible to collapse when unconfined. This may effect excavations and
result in additional earthworks and increased concrete volumes. Temporary shoring or Forma-Tube may be

required to retain the sands prior to concreting.

The samples classified on-site were assessed as having negligible plasticity, therefore laboratory testing was
considered unnecessary.

We have assessed the expected differential movement of the soil profiles encountered to be the equivalent
of a site with a Ys of less than 20mm.

For buildings within the scope of AS 2870-2011 a maximum allowable bearing pressure of 100 kPa is
available within the natural soils at the following depths:

 

[__ Test Site 1-1600mm_ _|__ Test Site 2- 1600mm |

 

The following foundation material will provide a safe bearing capacity (100 kPa) for buildings within the scope

of AS 2870-2011 and is shown shaded on the attached logs;

FOUNDATION MATERIAL - NATURAL MEDIUM DENSE SILTY SAND

5 SITE PREPARATION DETAILS

We recommend scraping this site free of all organic material and debris. The proposed construction areas
should then be cut and filled for the construction of a block base. The bases must be filled with a clean
material from the cut. The fill is to be free of organic material and have no clay content. In areas where the
excavator cannot access the fill is to be wetted and compacted in 150mm layers with a vibrating plate
making 6 passes (3 in each di ection). Temporary back Propping to the block base should be provided
throughout the compaction process. The fill is to be placed and compacted in accordance with AS3798-2007
to a level sufficient to achieve a Level 1 certification with a minimum relative field density of 95%. Copies of
compaction test results shall be presented to SCG Consulting Engineers for approval.

 

   

Where a retaining wall is required, a cut batter of 1 to 2 (vertical to horizontal) in the sand profile taken from
the base of the proposed wall should be excavated. These earthworks must incorporate shallow surface
spoon drains at the base and along the high side of the cut. Drains must have an efficient outflow down-
slope and clear of the construction area. The exposed face should also be protected against the potential for
stormwater erosion. Should these recommendations be un-achievable the builder should seek guidance
from this office on temporary shoring, benching or other suitable techniques.

SCG Consulting Engineers 2 SCG Ref: 23277(S)