RFI - Attachment C - Slope Stability Assessment and Geotechnical report · MCU20/0026

Project No. 1-22543                                                                                                          Page | 18
June, 2020
Ref: 1-22543, 2020-05-20, BR SSA VER 1
Sanya Holdings – Slope Stability Assessment and Geotechnical Report - Proposed Residence, 40 Park Crescent, Sunshine Beach




          The site being potentially subject to other factors resulting in foundation movement
           beyond the reactive soil movements resulting from moisture changes due to the normal
           site conditions described in AS 2870-2011 Clause 1.3.2 (i.e. Clause 1.3.3 abnormal
           moisture conditions).
          The site being potentially subject to landslip.

           6.2.3       Further Comments Regarding Foundations

Foundation Design

As noted above this site has been classified as ‘P’, however, if the site was classified based on
reactivity alone, under normal moisture conditions, a ground surface movement (ys) of <20mm
(maximum) could be adopted, which relates to a Class ‘A/S’ (sand-rock/slightly reactive) site
(considering the proposed development, existing subsurface profile as per boreholes records,
and taking into account other relevant geotechnical data held by Soil Surveys Engineering).

It should also be noted that the methodology adopted for determination of the site classification
assumes the structure has performance requirements similar to domestic type construction.

Development of Abnormal Soil Conditions

It is recommended that design works for the proposed development take into account the long
term effect of any design elements on the subsurface moisture conditions under and around the
structure.

These design works should consider aspects of the design that may contribute to the
development of abnormal moisture conditions i.e.:-

          Site drainage
          Gardens and landscaping
          Future planting of trees and shrubs
          Services and repair of leaks

The designer is directed to AS 2870-2011 Appendix B and Section 8.2.7 of this report which
outlines measures that should be considered.

           6.2.4       High Level Footings

Where high level footings are adopted, our recommendation is that all perimeter footings,
footings under isolated columns and strip footings below internal load bearing walls be founded
at least 300mm below platform level and a minimum of 300mm into the natural sands.

Table 6 outlines minimum allowable bearing capacities for high level foundations on the site.

 TABLE 6             ALLOWABLE BEARING CAPACITIES FOR HIGH LEVEL FOOTINGS
                                                                                              Allowable Bearing Capacity (kPa)
                                      Material
                                                                                              Strip Footing       Pad Footing
 Fill                       Uncontrolled                                                          NR                 NR
 Sand                       Loose                                                                 NR                 NR
                            Compacted to 70% density index                                        100                125
                            Medium Dense                                                          100                125
 Note: NR - Not Recommended



                                                                                                               SOIL SURVEYS