Attachment 5 - Geotechnical Assessment · MCU18/0015

RTI 11/055 Folio B398

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November 2003 -14- 03632248-001

 

Based upon our slope stability assessment in Section 6, piers or deeper pad footings must be
designed to resist lateral movement from:

e the sandy colluvium (up to about 1.5 m deep) on the eastern side of the creek where
ground slopes exceed 15° (includes Cabins 1A, 3A and 3C); and

e the very loose to loose sands (up to about 3 m deep) on the western side of the creek
below about RL 25 m (includes Cabins 1B, 1C, 2B and 2C).

Structures in these areas must also be braced at the surface to resist lateral movement.
7.4 Pavement Design

Design parameters for pavements will be dependent upon the subgrade materials present after
earthworks and the type, depth and quality of new fill used ¢o bring the site‘to\design levels.
The geotechnical laboratory testing from this site, together.with the test pit and borehole
results, indicate that the subgrade materials exposed following. earthworks may vary
dependent upon the location. CBR values assessed from the results ‘of this investigation, and
from previous experience, are provided in Table 6.

Table 6; Payement/Design Parameters

 

Design Comments
CBR’
(%)

5-15 Value to be adopted will be dependent upon
thickness and quality of fill placed.

 

 

 

3 Greater than laboratory result of CBR 1% (see
note 2).
5 Considered appropriate based upon experience

with similar materials.

 

10 Less than laboratory test result, however
considered suitable based upon our experience
with similar materials.

 

 

 

 

 

 

Note: 1. Pavement design parameters assume that ‘good’ drainage is installed and maintained.
2. Subgrades with CBR < 3% should be designed as per subgrades with CBR = 3% but with the initial
subgrade layer stabilised to a depth of 100-150 mm (eg. cement treated base).

Detailed subgrade evaluation should be undertaken during construction following earthworks
to confirm design CBR values and the extent of any subgrade stabilisation (if required). This
should comprise inspection by Golder Associates.

Golder Associates