Attachment F - Geotechnical Report

                              PROPOSED COMMERCIAL & RESIDENTIAL DEVELOPMENT
                              30-32 DOONELLA ST, TEWANTIN

5.3         Laboratory Testing
Shrink-Swell Index testing was carried out on two undisturbed samples. Table 1 below summarises the
results of this testing.
Table 1: Summary of Shrink-Swell Index Laboratory Testing

         BH No.                      Depth (m)                           Linear Shrinkage (%)


            BH1                        3.5-3.8                                        1.7


            BH3                        1.5-1.8                                        2.1



The above laboratory testing indicates that the natural silty clay materials tested are moderately reactive to
‘normal’ soil moisture content changes.

Table 2 below summarises the results of laboratory testing conducted on a bulk soil sample recovered from
the likely basement carpark subgrade in borehole BH1.
Table 1: Summary of CBR Laboratory Testing
                                 Maximum                                Optimum
                                                  Field Moisture
   BH No.         Depth (m)     Dry Density                             Moisture            CBR (%)    Swell (%)
                                                   Content (%)
                                   (t/m3)                              Content (%)

      BH1          0.8-1.1           1.69              23.8                19.5                2           3.9


CBR testing returned values of 2% for the natural silty clay sample from borehole BH1, at the approximate
proposed subgrade level. Field moisture content of the clay was 4.3% ‘wet’ of optimum moisture content.
The swell of 3.9% recorded was relatively high but is common when low CBR values are recorded.

Full test results are given on the laboratory certificates presented in Appendix B.




22 June 2018
Report No. 18151-001-Rev0                               6