Changes Application - MCU15/0023.02

Project No. 112.14608
January, 2013   REF: 1.14608, 2013.01.15, BR VER O.                                            Page 15

      Pile Capacities


      It is normal to limit the capacities of 500mm diameter grout injected piles to 1200kN and
      600mm diameter piles to 1500kN. If higher values are required, it is recommended that
      pile ioad tests be carried out.


      Pile Groups


      Where high column loads are involved, pile groups may need to be used to achieve the
      required load bearing capacities.


      Where pile groups are required, a pile spacing of not less than 2.5 times the pile diameter
      is recommended.           Larger pile spacings can be used if the efficiency of the pile group
      needs to be increased.          Table 5 indicates the relationships between pile spacing and
      group efficiency (after Tomlinson 1969).


      TABLE 5                         PILE GROUP EFFICIENCY
                            Pile Spacing                             Group Efficiency Ratio
                          2 x pile diameter                                    0.7
                          4 x pile diameter                                    0.8
                          6 x pile diameter                                    0.9
                     8 x pile diameter, or more                                1.0


   4.5   Retaining Walls

      Retention      systems     shouid be designed        in accordance   with AS 4678.2002    'Earth
      Retaining Structures'


      The lateral earth pressure from the active pressure wedge, where:.


                P           =         0.5 K,YH'
                P           =         active force resultant acting at a height of H/3
                                      from the base (kN/m run of wall)

                i'          =         density of sand, kN/m3
                H,          =         height of wall (m)
                K.          =         active pressure coefficient




                                                               ~    SOIL SURVEYS ENGINEERING