Appendix4-SlopeStabilityAssessment · MCU18/0135

Structures Engineering Design                                                                  18197-001-Rev0
                                                                                                 6 August 2018

The Ground Drill investigation comprised two boreholes drilled to depths of 4 m below ground level
(BGL), which encountered the following:

          Very loose sand to 1.4 m to 1.8 m depth; becoming
          Loose sand to depths of about 2.7 m depth
          Medium dense sand to the depth of investigation (i.e. 4.0 m BGL).

The Ground Drill investigation included dynamic cone penetrometer (DCP) testing to 4.0 m BGL which
has been used in assessing the above soil density descriptions.
Ground Drill classified the site Class P citing ‘poor bearing capacity’ as the reason. They also noted that
the ‘site would have the characteristics of a Class S site with a Ys (characteristic ground movement due
to moisture variation) of less than 20 mm if not a Class P site.
No groundwater seepage was recorded on the Global Testing borehole logs with the soils described as
‘moist’.

2.2       Topography
As illustrated in Text Figure 5, the site is located just below a topographical ridgeline formed to the west of
the site. The site slopes to the east/north-east at angles of between 5˚ and 7˚ across the building envelope
increasing to 12˚ to the east beyond the extent of the development area. Slope angles across the site were
measured using a hand held clinometer and are consistent with slopes interpolated from contour survey
information. Beyond the downslope site boundary the ground contours indicate a generally consistent slope
angle and direction.




Text Figure 5: Ground surface contours (courtesy Noosa Council Enterprise Mapping System)




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