Geotechnical Report

The poorly compacted surficial fill encountered in the investigation may extend across the site boundaries.
We therefore advise that sudden stop/start movements of any tracked equipment should be avoided in order
to reduce transmission of ground vibrations to any adjacent buildings and structures within or neighbouring
the site that are expected to be founded in the sands.



6.3.3 Seepage
Groundwater seepage was not encountered in the GeoCon2012 investigation and the DCP testing completed
by JKG did not indicate any traces of seepage within the 3.9m investigation depth. Elevated water levels are
expected for the wetland area to the north-east although the wetland area is lower than the site.

Some ephemeral seepage inflows may be encountered in the excavations, particularly after periods of heavy
or prolonged rainfall. In general, we expect that inflows, if any, to be of very small volume and managed by
infiltration into the sandy subgrade. Inspection and monitoring of groundwater seepage during excavations
is recommended, so that any unexpected conditions, which may be revealed, can be incorporated into the
drainage design.



6.4   Temporary Batter Slopes
Temporary batter slopes through the sandy soil profile no steeper than 1 Vertical (V) in 1.5 Horizontal (H) are
considered to be appropriate, though some surficial instability could still occur. These temporary batters will
be achievable within the site geometry.

Some instability of temporary sand batters may occur at, or below, the level of any groundwater seepage
should it occur, especially after rain periods, and sand bagging may be required to stabilise the lower portion
of these batters.

Stockpiles of construction materials, excavated materials etc must be kept well clear of the crests to avoid
surcharging the temporary batters, at a horizontal distance away from the cut batter slope crest equal to at
least twice the height of the cut batter.



6.5   Footing Design
The “uncontrolled” poorly compacted fill and very loose natural sands are not considered to be suitable
foundation materials due to their low bearing capacity, potential for high elastic settlements and their
susceptibility to additional settlements due to vibrations and infiltration of surface water run-off.

Based on our assessment of the GeoCon2012 investigation results and our additional DCP test results, the
natural sands of loose (or denser) relative density are considered to be a suitable foundation material. The
loose (or denser) sands are expected to be encountered from depths of between about 1.4m and 1.8m below
existing surface levels.


36409UR                                           11