Attachment 3 - Geotechnical Report

LOT 21 (16) PINES ROAD, COOROY                                   EBIS REFERENCE NO: 210417-SU/GEO



When building/construction works are complete a permanent all weather driveway will be
constructed.

Pavements should be sealed, either asphalt or concrete with adequate surface and
subsurface drainage provided.

5.2      Earthworks

Earthworks should be limited to building site preparation, access construction, service
trenching and site drainage.

Due to the moderate to steep slope of the site no unapproved earthworks (cut/fills) is to
take place in the designated building envelope unless certified by a suitable geotechnical
engineer.

Where not specifically shown or detailed on the Site Earthworks-Drainage plan by
E.B.I.S.(drawing number A3-210417-DW1) general requirements for earthworks and filling
on steep or sloping sites where approved by a suitable geotechnical engineer is:-

Cut embankments/batters where not retained should not exceed 1V:2H and must be
limited to no greater than 1 metre in height unless retained by an engineer designed
retaining wall structure.

Fill embankments should be keyed into the natural ground when constructed on slopes
greater than 15%.

All fill should be placed as controlled fill as defined in AS 3798 – “Guidelines on earthworks
for commercial and residential developments”.

For specific details refer to Site Earthworks – Drainage Plan A3-210417-DW1.

5.3      Foundations

We recommend that foundations for dwelling and associated structures be founded
into/on sound underlying weathered rock.


5.4      Surface Drainage

The site should be profiled prior to construction so that water drains away from the
proposed building works.

The site drainage should be maintained after completion of the building so that water does
not pond next to the footings.

On predominantly clay sites the moisture content of the soil should be monitored prior to
the commencement of construction and maintained as set out in the CSIRO publication
"Guide to Home Owners on Foundation Maintenance and Footing Performance".

Refer to CSIRO website www.publish.csiro.au/pid/7076.htm.

It is recommended surface water diversion swales be provided along the top side of the site
in the early stages of construction. Surface water should be directed to existing drainage
routes in undisturbed ground.

Swales should also be provided to redirect water immediately above any embankments,
retaining structures or earthworks areas. In addition, permanent drainage should be
provided behind any retaining structures.

Erosion and sediment control measures will be necessary during any earthworks.
PROPOSED NEW RESIDENCE                   PAGE 9 OF 10                                4 March 2022