Geotechnical report_Morrison · 132008.169

Job No. ME09/068

3. A post and panel arrangement or
4. A permanent concrete piled wall.

Options 1, 2 and 3 allow for construction in front with proper tanking and slope drainage.
Option 4 cannot be sealed properly unless a false wall is constructed in front and slab
drainage protection is formed between the two.

Design parameters for excavations to 4m.

Loose Dune Sand Density 17kN/m°

Ka 0.31 Temporary

Ko 0.50 Permanent

Kp 5.0 On benches
Medium Dense Dune Sand __ Density 48kNim*

Ka 0.27 Temporary

Ko 0.43 Permanent

Kp 7.8 On benches

Since the ground above the walls is level for all practical purposes, and since the swimming
pool outside the west boundary is on drilled piles, surcharge loadings on the retaining walls
will be small and a minimum allowance of 5kPa applies.

3.3. Building Support
3.3.1 Drilled Piles

Because of access restrictions it probably will not be possible to manoeuvre a large tracked
boring rig on this site. A pendulum type auger borer would probably be more convenient if
drilled concrete piles are considered. This matter should be discussed with potential piling
contractors.

Ground conditions will vary south to north over the site from essentially sand (Teewah sand)
to residual clay and sandstone. Dense to very dense sand was not found in BH2 with lesser
strength Teewah sand, clay and extremely low strength sandstone representing this part of
the site.

Design Parameters

 

Top Platform Bottom Platform

 

RL42.5 to 43.5m

RL39 to 40m

 

Minimum Depth 15m

Minimum Depth 15m*

 

Typical ‘N’ Value — 20 to 30

 

Typical ‘N’ Value — 20 to 30

 

 

* Unless sound rock is intersected at a lesser depth

 

 

120N

120N

 

 

 

 

 

 

 

 

As "= 1.0MPa As F = 1.0MPa
Top Platform Bottom Platform
Allowable Shaft Friction Allowable Shaft Friction
Sand - 25kPa Sand — 25kPa
Clay - 30kPa Clay — 30kPa
Ref 00558 — Adrian Slinger MORRISON GEOTECHNIC

71 Seaview Terrace Sunshine Beach