Sealed Judgement Neate 1219 of 2020 · MCU18/0015

The illustrative construction sequencing proposed in Attachment C to JER1 demonstrated the
complexity of the site topography and the construction techniques that will be required to
accommodate the geotechnical constraints required to maintain slope stability during the
construction period and in the long term (Paragraph 7.3 of JER). Similar sequencing will be
required for all structures, with the onsite experienced geotechnical engineer (Paragraph 7.4
of JER) to provide guidance.

The sequence essentially consists of commencement on the high western side of the site,
stabilising that by piling and retention, before excavation to the next level where further piling
is undertaken.

The site would thereby be progressively stabilised as construction moves downhill ensuring
all construction takes place under stable conditions and overall site stability is maintained.

This is elaborated on in the following sections.

Further to this, the following recommendations are iterated from the SSE letter of 3 July, 2023:

To address the geotechnical constraints, the following recommendations were made which
form the basis of any specification for building/development design and construction:-

   4) Footings (Sect 5.2 JER1)
       The entire proposed buildings and major retention structures must be supported on
       piled foundations designed to carry the structural loads and any potential lateral loads
       due to landslide. Final requirements are subject to detailed design.
   5) Retention
       All retention systems must be designed for both short term construction loads and long-
       term surcharge loads.
       Retaining walls must be designed for both local stability and global stability. This
       requires detailed stability analyses to assess required pile founding depths, pile
       diameter and spacing. This is detailed design.
       Core Consultants in their July, 2021 report established that piling will result in
       acceptable factors of safety against slope instability. Likewise, piling of structures will
       provide additional lateral resistance to slope instability.
   6) Earthworks
       Any filling should be undertaken after construction of engineer designed retaining
       walls.
       Any excavation below retaining structures can only be undertaken after stability of the
       retaining wall is established.
       I would recommend that the experienced geotechnical engineer providing site
       supervision (paragraph 7.4 of SJER) provides certification at each stage of excavation.
   7) Drainage
       The proposed stormwater disposal system (piped to creek) satisfies the requirements
       of JER1 and SJER (Geotechnical).
   8) On completion of all construction, a report providing certification from an RPEQ
      specialising in geotechnical engineering that all works have been undertaken in
      accordance with specifications and the site development has achieved suitable factors



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