Attachment 7B - Site Based Stormwater Manamgment Plan by ADG

Jun Of Of O4:S5p P-

Contral Facuitivs Building, Noosa Sanctuary

Geotechnical Reporl

Basement Design

General geotechnical parameters for retaining wall design in sands on the site are as follows:-

Soil Internal Angle of Friction 32 degrees

Sail Cohesion 0 kPa

Sail Unit weight 20 KN per cubic metre

Minimum Depth of Toe Footing 0.5 metres

Minimum Width of Toe Footing 0.6 metres

Allowable Bearing Capacity 100 kPa in medium densc to dense sands

Propped basement walls retaining drained sand or gravel may be designed assuming a rectangular
pressure distribution with a maximum earth pressure of 6H kPa acting over the wall where H is the total
depth of excavation in metres. Where the sand or gravel backfill is undrained. the triangular hydrostatic
pressure distribulion must be added to the earth pressures. This does not take into account any

additional lateral earth pressures produced by surcharges such as landscaping, adjacent structures or
vehicles or heavy cquipment. Lateral pressures due to shrink swell can be ignored

Should you wish to discuss any aspect of this report, please contact Ron McMahon at Coffey's
Maroochydore office,

For and on behalf of
COFFEY GEOSCIENCES PTY LTD

J

RON MCMAHON

 

Attachments : Iniportant Information about your Coffey Report
Figure 1- A Borehole Location

Borehole Logs

Coffey Geotuchnics
GCOTKPARI17BAAIA
6 June 2007