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

Project No. 1-22543                                                                                                          Page | 20
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




          Serviceability - Single piles and pile groups shall be designed for serviceability by
           controlling or limiting pile movements.
          Durability - This is outlined in Section 6 of AS 2159-2009 and will not be discussed any
           further here.
          Any other factors that need to be considered i.e. stability, scour, fatigue, cyclic loading or
           seismic actions - As we are not aware that any of these factors will affect the pile design
           they will not be considered any further.

The design geotechnical strength (Rd,g) can be calculated as the design ultimate geotechnical
strength (Rd,ug) multiplied by the geotechnical strength reduction factor (g). Uplift and lateral
capacities of piles are not considered, as these are both wholly dependent on the specific pile
type selected.

For design of piles in cohesionless soils, the following equations may be used. However, piling
contractors should be requested to provide their own calculations based on experience and
relevant pile load tests:-

           Rug         =           Q b + Qs
           Where:                  Qb          =           Ab Pd (Nq - 1)
           And:                    Qs          =           Ks Pd' tan d As
                                   Rg*         =           Rug x g
           Where:                  Rug         =           ultimate geotechnical strength of pile
                                   Qb          =           ultimate bearing capacity of pile base
                                   Qs          =           ultimate capacity of pile skin friction
                                   Rg*         =           allowable capacity of piles
                                   g          =           geotechnical strength reduction factor, adopt 0.5
                                                           but refer also AS2159-2009
                                   Nq          =           bearing capacity factor
                                   Pd          =           effective overburden pressure
                                   Pd'         =           effective overburden pressure at mid-layer height
                                   Ab          =           area of pile base
                                   As          =           circumferential area of pile
                                   Ks          =           earth pressure coefficient
                                   d           =           angle of wall friction

For this site and expected type of construction, the ultimate geotechnical strength pile
parameters for the material encountered on site are:-

          Base Bearing
                      Dense Sand = 900kPa
          Skin Friction
                      Loose Sand = Ignore
                      Medium Dense Sand = 10kPa



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