MCU14/0106 Appendix E - Engineering Report

2

oN

August 2004 -9- 04682104(AB)

 

Table 1 — Retaining Structure Design Parameters

 

 

 

 

 

Retained Material Unit Friction Lateral Earth Pressure Coefficient

 

 

 

 

 

 

Weight Angle
(tim) | (Degrees)

 

 

 

 

 

 

K, Ky K,
Medium Dene Sand L7 34 0.3 0.5 3.5
Stiff a Stffer) Clay 18 27 0.4 0.6 2.6
: ee i : : * * * * *

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note:

*: Variable dependent upon the type of material used and the degree of compaction achieved.

Positive permanent drainage must be. installed behind retaining walls unless they are designed
for development of full hydrostatic pressures.

6.3 Preliminary Footing Design

The investigation results indicate that the soils in the proposed excavation area should mostly
comprise low to medium plasticity sandy clay and, therefore, the resultant site classification
across the cut areas should typically be ‘M’ in accordance with AS2870-1996. An ‘M’
classification should also be achievable across the fill areas subject to the placement of any high
plasticity soils at least 1 m below the finished fill surface level.

High plasticity clays may be exposed at the cut subgrade level in the eastern part of the site and
partly across the ridge, these areas being primarily where pavements are proposed.

Building loads were not available at the time of reporting, however we are advised that the
proposed development will comprise low-rise commercial structures. The advice given below
is based upon the anticipated order of building loads together with site conditions following
proposed bulk earthworks.

Following earthworks to form the proposed site profile, the exposed building subgrade should
comprise mostly very stiff (or stronger) natural sandy clay or compacted fill. Conventional high
level strip or pad footings founded at least 600 mm below the finished ground level in the very
stiff natural clay or compacted fill may be designed using a preliminary allowable bearing
pressure of 150 kPa, for resultant total settlements of less than 25 mm.

Golder Associates