Reference Document - Slope Stability Risk Assessment

                                                                                            ABN: 26 602 913 673
                                                                                E: [email protected]
                                                                                               P: (07) 5568 0180
                                                                                  A: 5/10-12 Claude Boyd Parade,
                                                                                           Bells Creek, QLD, 4551
                                                                                         protestengineering.com




Figure 4 – Slope section east-west orientation (maximum angle 14.1‫)﮿‬




Figure 5 – Slope section south-north orientation (Maximum angle 4.26‫)﮿‬


SOIL PROPERTIES
Two boreholes undertaken by Protest have been used as a basis for the natural soil profile. Beneath
the topsoil/grass layer, residual, firm to very stiff clayey silts were encountered to borehole
termination at 2.0 m depth. Detailed borehole logs are attached. The clayey silts encountered were
classified as moist at the time of investigation. No Groundwater seepage was encountered at the time
of investigation.

RETAINING WALLS
All retaining walls should be designed as per AS4678. Any retaining walls are required to have a factor
of safety of 1.5 minimum. This office does not take responsibility for the integrity of any existing
retaining walls including rock walls, or future retaining walls unless specifically designed by this office.

RECOMMENDATIONS
    a. From our findings, the hazard risk of the natural slope is considered to be ‘Low’, which is
       should be acceptable.
    b. Attached are drainage and earthworks recommendations as per the Australian Geotechnical
       Society examples of good hillside construction practices. See AS2870 for further
       recommendations.
    c. Stormwater is to follow a stormwater management plan.
    d. Effluent disposal may be by use of trenches.




PTP/03499 – 328 Upper Pinbarren Road, Upper Pinbarren (Mango Tree Cabin)                           13 July 2019