Geotechnical Investigation Report · OPW26/0149

                                                                                                  PTG/04982 – 0001 – Rev0 – Rev0



Table 1: Summary of Material Depths Encountered in Boreholes

             Strata                              BH01                     BH02                           BH03
  Firm to Stiff silty CLAY           0.0 – 1.3                             n/a                            n/a
   Stiff to Very Stiff silty
                                        n/a                              0.0 – 1.5                      0.3 – 1.0
            CLAY
  Very Stiff to Hard silty
                                        n/a                                n/a                          0.0 – 0.3
            CLAY
      Hard silty CLAY                1.3 – 6.0                           1.5 – 6.0                      1.0 – 6.0
 Notes:
     a. All depths shown are in metres below ground level
     b. n/a = material not encountered
     c. Values in bold indicate borehole termination depth


Notably, our investigation did not encounter any pre-existing, non-engineered fill.

     6.2           Groundwater
Groundwater was not encountered in any of the boreholes. It should be noted that groundwater levels can be perched,
and/or can fluctuate seasonally, and also during and after heavy/prolonged rainfall events. Given this natural
variability, it is prudent to assume that water levels can fluctuate.



7 LABORATORY TESTING AND RESULTS
NATA accredited laboratory testing was undertaken on selected representative soil samples recovered from the
boreholes in accordance with ‘AS1289-Methods of Testing Soils for Engineering Purposes’. The purpose of the
laboratory testing was to determine typical soil and rock behaviour characteristics for engineering assessment. Copies
of the laboratory reports are presented in Appendix 3; the results of the testing are summarised in Table 2, Table 3,
Table 4, and Table 5 below.


Table 2: Summary of Atterberg Limits Testing

 Borehole
                 Depth (m)            Material            WL (%)         WP (%)             IP (%)              LS (%)
   No.
   BH02           0.3 – 1.6          Silty CLAY                69           30                   39                 12
   BH03           0.4 – 1.0          Silty CLAY                45           21                   24                 9
 Notes:
      •    WL = Liquid limit; Wp = Plastic limit; Ip = Plasticity index; LS = Linear shrinkage


Table 3: Summary of Shrink-Swell Index Testing

 Borehole                                                                                 Shrinkage
                 Depth (m)            Material           IMC(%)         FMC (%)                                 Iss (%)
   No.                                                                                       (%)
   BH01           0.6 – 1.2          Silty CLAY                21.4        33.2              26.2                   1.9
   BH02            0.5 – 1.2         Silty CLAY                24.6        27.0                  23.7               1.1
 Notes:
      •    IMC = Initial Moisture Content
      •    FMC = Final Moisture Content




                                                                                                                          8