Avocet Pde OPW - App E Slope · OPW20/0092

                                                                                               37 636 783 527

                                                                                                  PO BOX 851
                                                                                      Moffat Beach, QLD, 4551
                                                                              [email protected]
                                                                                www.geotechengineering.com.au




2.5 Structures
At the time of the inspection, several structures were onsite that could be observed externally
without intrusive investigation. The existing structures and retaining walls typically appeared
to be performing in accordance with a structure under normal conditions suggesting no
shallow soil creep occurring. A timber fence along the northern boundary of the property has
tilted; however, it appears to be due to insufficient lateral resistance to for wind loading.

2.6 Fieldwork & Results
The fieldwork was undertaken on 23 Apr 2020 and included 3 bores drilled to to a maximum
depth of 3.5 m using a 4WD mounted auger drill rig. Any exposed faces were also inspected
to inform the results of the investigation. The subsurface conditions were logged through
tactile and visual assessment of returned spoil by an experienced geo-technician from Global
Testing.


The encountered subsurface conditions are described in detail on the attached bore logs;
however, in summary comprise minor fill over sand of loose density grading medium dense
typically below 1.0 m depth as described in the Global Testing investigation report 200309..


Groundwater measurements or the lack of groundwater are made within the bore logs
attached; however, it must be noted that groundwater is transient and will fluctuate with
seasons and time.

3.0 Land Stability

3.1 Explanatory Notes
Local authorities prepare mapping tools to aid in assessing potential slope stability
requirements. It is important to note that where a site specific investigation and slope stability
assessment are undertaken, they take precedence.


Landslides are caused where a soil or rock mass has a decrease in strength, usually attributed
to groundwater, resulting in the material not being able to maintain its own self-weight
resulting in a slope failure.


The Australian Geomechanics Society (AGS) developed a set of tools and procedures for
assessing the stability of a slope. The tools and procedures presented with the AGS
documentation form the basis of the assessment undertaken herein and their documentation
is attached for reference.


The guidelines also identify that the regulator typically sets the standard for levels of tolerable
risk. AGS defines tolerable risk as “risks within a range that society can live with so as to secure




29 Apr 2020                                                          Proposed Residnetial Dwelling