Geotech Report · MCU19/0008.02

Project No. PG-2096                                                                                                                 Page | 7
December 2022
Ref: PG-2096, 2022-11-03, GR VER 1
Keith & Jeannette Ince – Geotechnical Stability Assessment - Proposed Residence, 22 Arakoon Crescent, Sunshine Beach




                       FIGURE 1                ULTIMATE LATERAL RESISTANCE OF PILES

TABLE 2                DESIGN VALUES FOR LATERAL PILE CAPACITY CALCULATION

                                                                                                                       Bulk Density 
                              Material                                                Design Kp
                                                                                                                          (kN/m3)
                                               Loose                                       2.56                              18
            Sands                           Medium Dense                                   3.0                              18.5
                                               Dense                                       3.25                              19

Should a 'working stress' approach be adopted, a factor of safety of between 2.5
and 3.0 should be adopted.

Lateral capacity may be achieved through the use of raked screw piles etc. if
required.

Construction Considerations

Given the non cohesive soil conditions encountered on site, it is likely that a bored
pier type foundation system will not be appropriate as side wall collapse of the piers
is likely to occur. Appropriate piling solutions could include CFA piles or possibly
screw piles, however screw piles are unlikely to provide significant lateral capacity
and a combination of vertical and raked piles may be required.

During construction, all piles must be inspected by a geotechnical engineer to
confirm the geotechnical strength parameters presented in Table 1 and Table 2 and
to check the capacity of the piles.

8.0 RETAINING WALLS

Retaining walls up to 3m in height may be required as part of the development.
Walls should be specifically engineer designed in accordance with AS 4678-2002
(Ref 9).