Slope Stability Report

5.0 GEOTECHNICAL INVESTIGATION
5.1       Fieldwork

Three (3) bore holes were undertaken across the site using a mechanical push tube to a maximum
depth of 1.5 metres. Dynamic Cone Penetrometer (D.C.P) tests were undertaken at the time of the
site investigation. The bore holes were drilled using solid flight augers fitted with a steel ‘V’ shaped
bit or tungsten carbide bit.

An authorised representative from STA Consulting Engineers set out the bore holes locations from
existing site features, directed sampling and logged bore hole profiles. Engineering logs of the bore
holes are presented in Appendix A, together with Explanation Sheets defining the terms and symbols
used in the preparation of the logs.

5.2       Subsurface Conditions

The sequence encountered by the bore holes typically included a medium dense to dense sand for
the extent of the test holes undertaken. Uncontrolled fill comprising of a silty sand was identified in
test hole # 3 only. The following table is a summary of the subsurface profiles observed:‐
Bore Hole Summary
  Bore        Uncontrolled Fill (m)   Silty Sand (m)          Sand (m)              Termination Depth
  Hole #                                                                            (m)
  BH # 1                ‐                   0.0 ‐ 0.2              0.2 – 1.5               1.5 m
  BH # 2                ‐                   0.0 ‐ 0.2              0.2 – 1.5               1.5 m
  BH # 3            0.0 – 0.8                   ‐                  0.8 – 1.5               1.5 m

5.3       Groundwater
Groundwater was not identified at the time of the subsurface investigation. It must be noted that
ground moisture and ground water depths are typically influenced by climatic conditions and the
permeability of the soils observed and may vary with seasonal change.

6.0 SLOPE STABILITY ASSESSMENT
6.1       Stability Assessment Findings
At the time of the site assessment, the following observations were made:‐

         Topographically the site is positioned on the upper slopes of the undulating dune surface.
         The predominate land shape is Planar.
         The natural unaltered slope is considered moderate with a general cross fall sloping from the
          North East to the South West, estimated at approximately 7 to 8 degrees.
         From visual assessment only, it appears cut and fill earthworks had been conducted to
          accommodate the existing residence.
         The site is connected to the mains storm water and sewer networks, therefore all outflows
          are to be directed to these mains..
         No ground water or surface water seepage was observed, nor was any vegetation such as
          reeds/ sedge grasses typically associated with wet areas identified.
         No tension cracks were observed on or across the slope within the vicinity of the site.
         Hummocky or bulging soils were not identified on or at the base of the slope within the
          vicinity of the site.