Appendix G - Geotechnical Report

Total Concept Homes                                                                                20332-001-Rev0
                                                                                                 15 December 2020

suggests that weathered rock could be expected within 1 m to 1.5 m of the ground surface. Such materials
may require the use of ripping attachments, or selected pneumatic breaking.

Temporary batters in natural soils of stiffer (or stiffer) consistency, and future controlled fill may be formed at
1V:1H; with permanent batters formed no steeper than 1V:2H. Flatter batters may be required if
groundwater seepage is encountered. Permanent batters will require erosion protection such as covering
with erosion matting or vegetation. Where spatial constraints prevent adoption of the above recommended
batter slopes, cut or fill batters would need to be supported by retaining walls.

The above recommendations do not supersede any existing safety regulations or legislation applicable to
excavations (e.g. limits on personnel entry into trenches).

Any excavations required adjacent to existing structures, will need to be specifically designed to ensure that
the structures are not adversely affected (e.g. 'undermined').

Ground surfaces should be graded to shed surface water runoff away from construction areas. It should be
noted that during wet weather, the natural soils may cause turbid stormwater run-off. Appropriate erosion
and sediment control measures must be installed prior to commencement of earthworks at this site,
especially given the presence of natural gullies and dams within the site boundary downslope of the
proposed construction areas.

4.3    Footing Design
Footings for the proposed building and any ancillary structures (e.g. retaining walls) must penetrate through
any future fill to ‘socket’ at least 0.5 m into natural residual soil comprising stiff (or stiffer) clay or a minimum
of 0.3 m in to weathered rock. Based on the Ground Drill boreholes, depending on the construction
methodology adopted, normally dimensioned, conventional high-level footings would be appropriate, or
possibly extended locally via the use of steel reinforced concrete bored piles (or ‘bucket piles’).

Footings could be designed with an allowable bearing capacity of 100 kPa when founded in stiff (or stiffer)
natural residual clays or 400 kPa in weathered rock.

Footing design should also account for the characteristic surface movement (ys), indicated by the site
classification report by Ground Drill to be equivalent to Class M. The re-use of the site-won clay materials for
filling works could result in greater estimates of characteristic ground surface movement and should be
considered by the design engineer once earthworks details have been confirmed.

All footings should found such that they are not adversely affected by any adjacent excavations, batter
slopes, trenches, or retaining walls that are not designed to support building loads. Footings should found at
least below a plane extending 1 m horizontally from the base of trenches/excavations/retaining walls, then
rising up at 1V:1H, as illustrated in Text Figure 10 overleaf.




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