Attachment 5 - Geotechnical Report · MCU18/0015

J000635-002-R-Rev1                                                                                                    November 2018


1.0       INTRODUCTION
As requested by Innovative Planning Solutions Pty Ltd (IPS), this report responds to Items 1 to 7, 10 and 13
in Noosa Council’s information request MCU18/0015 (IR) regarding a proposed development at 27 Attunga
Heights, Noosa Heads.
A geotechnical report for a proposed development on the site was undertaken by Golder Associates in 2003
(refer report 03632248-001). Further geotechnical assessment was provided by Core Consultants in 2015
(refer report J000128-001-L-Rev0) following an amendment to the proposed development layout. The layout
has changed again since our 2015 report, and this report addresses the currently proposed development,
based on architectural plans produced by Tim Ditchfield Architects (refer Project No. 1830, DWG No. DD 02
– P2, dated September 2018).
The IR items and our responses are summarised in Table 1.
Table 1: Summary of Geotechnical Items from Noosa Council Information Request, and associated responses.
      Item                            Information Required                                               Response
       1            “Update the Golder Associates and Core Consultants reports        This report addresses the current development
   (Available       to address the geotechnical design and construction issues        layout.
    Reports)        relevant to the currently proposed development layout.”
      2             “Provide an accurate slope analysis plan of the site.”            Refer to the attached Figure 1.
(Slope Angles)

      3
                    “Provide information on the subsurface conditions                 Refer to Section 5.2 for subsurface conditions,
                    downslope of the units and towards the creek to assess            and Section 7 for slope stability assessment.
 (Subsurface
                    stability on site. Provide an assessment of the ground
  Conditions)
                    conditions in relation to the stability of the site.”
                    “Provide information to monitor and maintain water quality of     The information required is not of a
                    the creek, both during construction and the proposed use of       geotechnical nature and does not relate to the
       4            the site.”
(Slope Stability)
                                                                                      issue described in Item 4 (i.e. slope stability).
                                                                                      Refer to Section 7 for slope stability
                                                                                      assessment.
      5             “Provide information regarding the stabilisation of the site,     Refer to Section 7 for slope stability
 (Overview of       both during construction and the proposed use of the site.”       assessment and Sections 6 and 7 for
 Approach to                                                                          associated recommendations regarding
Slope Stability)                                                                      stabilisation of the site.
                    “i. Advice is required on the locations to which the footing      i. The footing advice in the Golder report and
                    design recommendations apply. Do these recommendations            the recommendations in this report should
                    apply to all footings or only those footings within 20 m of the   apply to all footings
                    creek?
       6                                                                              ii. Refer to Section 6.3 for lateral load
                    ii. The method to be adopted in estimating the lateral loads
   (Footings)
                    on the piles should be confirmed. There are several               calculations
                    approaches available for this design.                             iii. Refer to Section 6.3 for geotechnical design
                    iii. The geotechnical design parameters to be adopted in the      parameters
                    design should be confirmed”
                    “i. Slope stability analyses should be provided to show that      i. Refer to Section 7 for slope stability
                    the proposed filling and retention system has an adequate         assessment
                    factor of safety against both local and global instability.       ii. Refer to Sections 6.1.1 and 6.1.3 for site
                    ii. Site specific recommendations are required on site
                                                                                      preparation recommendations
                    preparation prior to filling given the presence of very loose
       7            and loose sand.                                                   iii. Refer to Section 6.3 for footing
    (Access         iii. Site specific recommendations are required on footing        recommendations
   Driveway)        designs for the proposed retaining walls given the presence       iv. Refer to Section 6.3 for footing
                    of loose to very loose sand.                                      recommendations, and refer to Section 6 for
                    iv. The geotechnical design parameters to be adopted in the       other design recommendations
                    design should be confirmed. Clear advice also needs to be
                    given in relation to accommodating other relevant site factors
                    into the design.”
      10            “Provide full details as to how excavations on the site for the   Refer to Sections 6.1 and 6.2 for excavation
  (Retention        proposed development layout are to be constructed and the         support recommendations
 Systems for        retention systems to be employed to avoid causing instability
 Excavations)       both during and post construction.”
                    “Provide an independent slope stability assessment and            This report provides geotechnical
                    geotechnical report for each of the proposed allotments. If       recommendations and slope stability
       13           appropriate, recommendations on measures to stabilise the         assessment for Lots 1 to 3 as shown on the
                    land or maintain stability should be included.”
(Proposed Lots                                                                        attached Figure 1. Lot 4 has been excluded
  2, 3 and 4)                                                                         from the currently proposed development
                                                                                      layout. Refer to Section 7 for slope stability
                                                                                      assessment and Sections 6 and 7 for


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